CN112512926A

CN112512926A - Apparatus and method for vacuum skin packaging of products and skin packaged products

Info

Publication number: CN112512926A
Application number: CN201980052789.6A
Authority: CN
Inventors: C·谢瓦利埃; A·利佩罗蒂; I·蒂贝
Original assignee: Cryovac LLC
Current assignee: Cryovac LLC
Priority date: 2018-08-08
Filing date: 2019-08-07
Publication date: 2021-03-16
Anticipated expiration: 2039-08-07
Also published as: EP3833603A1; WO2020030717A1; US11407537B2; CN112512926B; US20210292019A1

Abstract

Disclosed is a process for packaging a product arranged on a support, the process comprising: providing a plastic film over the support, wherein the product is arranged between the support and the film web; and securing the membrane tightly to the support with air. The process is carried out using an apparatus for packaging comprising a film supply assembly and a base device having an upper side defining one or more receiving areas, each of said receiving areas being configured for receiving at least one respective product-containing support; the upper tool is configured to hold the film portion above the product-containing support and then heat seal the film portion to the product-containing support. Each receiving area has a flat portion and an elongate feature that projects above the plane of the flat portion. Also disclosed is a packaged product obtainable by the process and apparatus.

Description

Apparatus and method for vacuum skin packaging of products and skin packaged products

Technical Field

The present invention generally relates to an apparatus and method for packaging of products. In one aspect, the present invention relates to an apparatus and method for vacuum skin packaging of a product. The invention also relates to a skin packaging product. In particular, the present invention relates to a skin packaging product obtainable with said vacuum skin packaging apparatus or method.

Background

Packaging of products requires the application of a plastic film sealed over a support containing the product. In particular, vacuum skin packaging is a process for packaging a wide variety of products, particularly perishable goods such as food products such as fresh or frozen meat, fresh or frozen fish, cheese, processed meat products, ready meals and the like. In the vacuum skin packaging process, the product is placed on a support (e.g., a flat tray or a tray with side walls) and then the support, with the product placed thereon, is placed in a vacuum chamber where a film of plastic material is applied to the support containing the product. In more detail, the vacuum chamber comprises a top tool designed to hold the plastic film in position above the support filled with the product using vacuum means. The top tool is also designed to heat and soften the plastic film so that the plastic film acquires the necessary deformability and tackiness. While the plastic film is held at a distance above the support filled with product by vacuum, the volume between the support and the film is evacuated from the air. A re-venting step is then carried out in which the vacuum holding the thermoplastic film is released to cause the film to drop around the product and seal to the surface of the support not covered by the product, thus forming a tight fit around the product and on the support.

For cost reasons and with the aim of reducing any scrap as much as possible, the support used in the packaging process described above has a reduced wall thickness. In another aspect, the support may be flat or substantially flat, or at least comprise a flat or substantially flat main portion onto which the product is positioned. Thus, the entire support or at least a major part thereof exhibits little resistance to deformation directed out of the plane of the flat support or flat part of the support. These conditions may play a negative role because, after the plastic film is applied to the support, the heated plastic film cools and shrinks in a manner generally different from the underlying support and to such an extent as to cause the formation of bends or undulations in the support. Obviously, the undulated support or the support with curved portions seriously impairs the aesthetic appearance of the packaged product, rendering it very difficult to stack even when it has a laminar configuration, and in extreme cases also potentially impairs the reliability of the sealed connection between the plastic film and the underlying support.

Disclosure of Invention

It is therefore an object of the present invention to provide an apparatus and method that adequately addresses the problems highlighted above.

In particular, it is an object of the present invention to provide a packaging method and apparatus which can reduce or avoid out-of-plane deformations in the support under the product during or after the packaging cycle, so that undulations or bends in the support packaging the product are minimized. Additionally, it is an object of the present invention to provide an apparatus and process that solves the above identified problems without compromising on the overall packaging cost and, therefore, without requiring the use of thicker supports.

Furthermore, it is an object to provide a method and an apparatus which can be implemented without requiring complex changes to conventional packaging systems and without compromising the stage or duration of the packaging process.

A further subsidiary object is an apparatus and a method capable of solving the problems identified above and thus improving the aesthetic appearance of the final packaged product.

At least one of the above objects is substantially achieved by an apparatus and a method according to one or more of the appended claims.

Apparatus and processes according to aspects of the present invention and capable of achieving one or more of the above objects are described herein below.

The 1 st aspect relates to a device for packaging products arranged on a support (2), comprising:

-a film supply assembly (3) configured for supplying a plastic film (4);

-a base device (6) having an upper side (7) defining one or more receiving areas (8), each configured for receiving at least one respective support (2) filled with a product;

-an upper tool (10) operating above the base means (6) and configured for holding the film portion (4 a) of said plastic film (4) above the at least one product-containing support (2) positioned in the respective receiving area, the upper tool (10) and the base means (6) being configured to cooperate for heat-sealing the film portion (4 a) to the at least one product-containing support (2).

In the 2 nd aspect according to the 1 st aspect, each reception area (8) includes: a flat portion (80) extending on a predetermined positioning plane (81) and defining a majority of the surface of the receiving area (8); and one or more elongate features (82) projecting above the plane of orientation of the planar portion (80).

In aspect 3 according to the preceding aspect, each of the elongate features (82) in each receiving area (8) projects above the locating plane (81) to define a feature height (h) above the locating plane (81) to be comprised between 0.1 and 2.0 mm.

In a 4 th aspect according to the 2 nd or 3 rd aspect, each receiving area (8) has a flat surface of at least 75%, wherein the elongate features are narrow and elongate and represent a unique discontinuity in the planarity with the receiving area.

In a 5 th aspect according to the preceding aspect, each receiving area (8) has a flat surface of at least 85%, wherein the elongate features are narrow and elongate and represent a unique discontinuity in the planarity with the receiving area.

In a 6 th aspect according to the preceding aspect, each receiving area (8) has a flat surface of at least 95%, wherein the elongate features are narrow and elongate and represent a unique discontinuity in the planarity with the receiving area.

In aspect 7 according to any one of aspects 2 to 6, each of the elongate features (82) has a length measured along the elongate feature and parallel to the locating plane (81) that is at least 10 times the width of the elongate feature.

In an 8 th aspect according to any one of the 2 nd to 7 th aspects, each of the reception areas (8) is in the form of a rectangle.

In a 9 th aspect according to the preceding aspect, each of the elongate features (82) is in the form of a continuous rib extending across the respective receiving area and having a length which is at least 75%, optionally at least 90%, of the length of the longest side of the rectangle.

In a 10 th aspect according to the preceding aspect, each of the elongate features (82) is in the form of a continuous and straight rib extending across the respective receiving area and having a length which is at least 75%, optionally at least 90%, of the length of the longest side of the rectangle.

In an 11 th aspect according to any one of the 2 nd to 7 th aspects, each of the reception areas is in the form of a circle.

In a 12 th aspect according to the preceding aspect, each of the elongate features (82) is in the form of a continuous rib extending across the respective receiving area and having a length that is at least 75%, optionally at least 90%, of the length of the circular diameter.

In a 13 th aspect according to the preceding aspect, each of the receiving areas is in the form of a circle and each of the elongate features (82) is in the form of a continuous and straight rib extending across the respective receiving area and having a length that is at least 75%, optionally 90%, of the length of the diameter of the circle.

In aspect 14 according to any one of aspects 2 to 13, the one or more elongate features (82) are symmetrically positioned with respect to a longitudinal axis of symmetry of the receiving area.

In a 15 th aspect according to the preceding aspect, wherein each receiving area is in the form of a rectangle and the one or more elongate features (82) are symmetrically positioned with respect to a longitudinal axis of symmetry extending parallel to the two long sides of the rectangle and through the centre of the rectangle.

In a 16 th aspect according to any one of the 2 nd to 15 th aspects, each of the elongate features (82) is defined by a respective elongate element removably engaged to the upper side of the base means (6).

In a 17 th aspect according to any one of the 2 nd to 16 th aspects, the elongate feature (82) comprises: one or more first elongate features (83) extending along a first direction; and one or more second elongate features (84) extending along a second direction at an angle to the first direction.

In an 18 th aspect according to the preceding aspect, the elongate feature further comprises a third elongate feature (85) extending transverse to both the first and second elongate features.

In a 19 th aspect according to any one of the 2 nd to 18 th aspects, the elongate feature (82) comprises a portion extending in correspondence with a peripheral band that surrounds a central region of the respective receiving area.

In a 20 th aspect according to the preceding aspect, the elongate feature (82) comprises at least one annular feature extending along the peripheral band.

In a 21 st aspect according to any one of the 2 nd to 20 th aspects, each of the elongate features (82) exhibits a rounded top profile in cross-section.

In a 22 nd aspect according to any one of the preceding aspects, the base means (6) comprises a lower tool (11) cooperating with the upper tool (10), in correspondence with the packaging station (5) of the apparatus, and wherein the upper tool (10) and the lower tool (11) are relatively displaceable between:

-a first operating condition, in which the upper tool (10) is sufficiently spaced from the lower tool (11) to allow positioning one or more of said product-containing supports (2) below said membrane portion (4 a) held by the upper tool (10), and

-a second operating condition, in which the upper tool (10) is approached with respect to the lower tool (11) and is configured to heat-seal said at least one film portion (4 a) to said at least one underlying support (2) containing the product.

In a 23 th aspect according to the preceding aspect, the apparatus comprises a vacuum arrangement (13) configured for removing air from at least a volume between the at least one film portion (4 a) and the one or more product-containing supports (2) in the packaging station (5).

In a 24 th aspect according to the preceding aspect, the apparatus further comprises suction apertures (18) distributed on the active surface (17) of the upper tool (10) and connected with the vacuum arrangement (13) or auxiliary vacuum arrangement (22).

In a 25 th aspect according to the 23 th or 24 th aspect, the apparatus additionally comprises a heater (21) configured to heat at least a portion of the upper tool action surface (17).

In a 26 th aspect according to the preceding aspect, the apparatus further comprises a control unit (100) configured for controlling the upper tool (10) and the lower tool (11), the heater, the vacuum arrangement and optionally the auxiliary vacuum arrangement.

In the 27 th aspect according to the foregoing aspect, the control unit (100) is configured to execute the following cycle:

-causing the positioning of the upper tool (10) and the lower tool (11) in a first operating condition,

-in the case where the upper tool (10) and the lower tool (11) are in a first operating condition,

o-commanding one of a vacuum arrangement (13) or an auxiliary vacuum arrangement (22) to cause suction of gas through the suction aperture (18) and holding the membrane portion (4 a) against or close to the active surface (17),

o commanding the heater (21) to cause heating of at least a portion of the film portion (4 a) held by the upper tool (10),

-causing the upper tool (10) and the lower tool (11) to move to a second operating condition,

-in the case where the upper tool (10) and the lower tool (11) are in the second operating condition,

o commanding a vacuum arrangement (13) to draw gas present between said at least one membrane portion (4 a) and the underlying support (2) containing the product,

o commanding one of the vacuum arrangement (13) or the auxiliary vacuum arrangement (22) to cause the expulsion of gas through the suction orifice for re-evacuation to release the film portion (4 a) from the upper tool (10) active surface and drop the film portion (4 a) onto the support (2) containing the product, the film portion (4 a) being heat-sealed to the upper surface of the support (2) not covered by the product, thereby forming at least one vacuum skin-packaged product.

In a 28 th aspect according to the 22 th aspect, the apparatus comprises a conveyor (12) configured for displacing one or more product-filled supports (2) along a predetermined path at least from a product loading station (9) to said packaging station (5).

In a 29 th aspect according to the preceding aspect, the apparatus additionally comprises a vacuum arrangement (13) configured for removing air from at least a volume between said at least one film portion (4 a) and said one or more product-containing supports (2) in the packaging station (5).

In a 30 th aspect according to the preceding aspect, the apparatus additionally comprises suction apertures (18) distributed on the active surface (17) of the upper tool (10) and connected with said vacuum arrangement (13) or auxiliary vacuum arrangement (22).

In a 31 st aspect according to any one of the preceding three aspects, the apparatus additionally comprises a heater (21) configured to heat at least a portion of the upper tool action surface (17).

In a 32 th aspect according to the preceding aspect, the apparatus additionally comprises a control unit (100) configured for controlling the conveyor (12), the upper tool (10) and the lower tool (11), the heater, the vacuum arrangement and optionally the auxiliary vacuum arrangement.

In the 33 th aspect according to the foregoing aspect, the control unit (100) is configured to execute the following cycle:

o commanding the heater to cause heating of at least a portion of the film portion (4 a) held by the upper tool (10),

o causing a conveyor (12) to position one or more of said product-containing supports (2) on respective receiving areas (8) of a base device (6) below said film portions (4 a) held by an upper tool (10),

o commanding one of the vacuum arrangement (13) or the auxiliary vacuum arrangement (22) to cause the expulsion of gas through the suction orifice (18) for re-evacuation to release the film portion (4 a) from the upper tool (10) active surface and drop the film portion (4 a) onto the support (2) containing the product, the film portion (4 a) being heat-sealed to the upper surface of the support (2) not covered by the product, thereby forming at least one vacuum skin-packaged product.

In a 34 th aspect according to any one of the 22 th to 27 th aspects, the receiving area (8) is defined on an upper side of the lower tool (11), the upper side directly facing the upper tool (10).

In a 35 th aspect according to any one of the 28 th to 33 th aspects, the receiving area (8) is defined on an upper side of a conveyor (12) configured to traverse the packaging station (5) above the lower tool (11).

The 36 th aspect relates to a process for packaging a product arranged on a support (2) using the apparatus according to any one of the preceding claims.

A 37 th aspect according to the preceding aspect relates to a packaging process, wherein the process comprises the steps of:

-supplying a plastic film (4) from a film supply assembly (3);

-placing at least one support (2) containing a product on a respective receiving area (8) of a base device (6);

-keeping the film portion (4 a) of the plastic film (4) above at least one product-containing support (2) positioned in the respective receiving area (8);

-heat-sealing said at least one film portion (4 a) of said plastic film (4) to said at least one respective one of said product-containing supports (2).

The 38 th aspect relates to a process for packaging a product arranged on a support (2) using the apparatus of any one of the 22 th to 35 th aspects, wherein the packaging process comprises the steps of:

-positioning the upper tool (10) and the lower tool (11) in a first operating condition;

o sucking gas through said suction orifice (18) and holding the membrane portion (4 a) against or close to said active surface (17),

o heating at least a part of the film portion (4 a) held by the upper tool (10),

o placing at least one support (2) containing the product on a respective receiving area (8) of the base device (6) below said membrane portion (4 a) held by the upper tool (10),

-moving the upper tool (10) and the lower tool (11) to a second operating condition;

o extracting the gas present between said at least one membrane portion (4 a) and the underlying support (2) containing the product,

o re-venting the gas through the suction orifice (18) and releasing the film portion (4 a), thereby allowing the film portion (4 a) to drop and heat-seal to the support (2) containing the product, thereby forming at least one vacuum skin-packaged product (P).

In a 39 th aspect according to the preceding aspect, during the re-venting step, the one or more supports (2) are pressed against the respective receiving areas, causing the formation of an elongated ridge (93) on the top surface of the support (2) and a corresponding elongated indentation (94) on the bottom surface of the support (2), the elongated ridge and underlying elongated indentation being of a shape opposite to the elongated feature (82) present on the receiving area.

In a 40 th aspect according to any one of the 36 th to 39 th aspects, each of the one or more supports (2) presents:

a sheet body having a top surface, a bottom surface and a thickness,

-one or more preformed elongated ridges protruding from the top surface, and

-one or more pre-formed elongated indentations on the bottom surface extending along and corresponding to the elongated ridge.

In a 41 th aspect according to the preceding aspects, the top and bottom surfaces of the sheet body are flat without the inclusion of the elongate ridge and the elongate indentation and extend along respective parallel top and bottom planes.

In a 42 th aspect according to either of the two preceding aspects, the pre-formed elongate indentation of each support (2) is positioned over and engages a corresponding elongate feature (82) present on a respective receiving area defined in the base component (6).

In a 43 th aspect according to any one of the preceding three aspects, each of the elongated ridges protrudes above the top plane to define a ridge height comprised between 0.1 and 2.0 mm.

In a 44 th aspect according to any one of the preceding four aspects, wherein each of the elongate ridges exhibits a rounded top profile in cross-section.

In the 45 th aspect according to any one of the 36 th to 44 th aspects, the plastic film heat-sealed to the product-containing support (2) and the product-containing support (2) are made of respective different materials.

In a 46 th aspect according to any one of the 36 th to 45 th aspects, the coefficient of linear expansion per degree celsius of the plastic film in at least one direction is greater than the coefficient of linear expansion per degree celsius in the same direction of the underlying support (2) at atmospheric pressure and at least in the interval between 20 ℃ and 100 ℃.

In a 47 th aspect according to any one of the 36 th to 46 th aspects, the support (2) presents a thickness comprised between 0.10 mm and 2.00 mm.

In a 48 th aspect according to any one of the 36 th to 47 th aspects, the support (2) is formed by one of:

-a sheet of paper,

-a sheet of paperboard,

-a multilayer structure comprising at least one paper layer and at least one paperboard layer,

-a multi-layer structure comprising a plurality of paper layers,

-a multilayer structure comprising a plurality of paperboard layers,

-a sheet of plastic material,

-a multilayer structure comprising a plurality of plastic layers,

-a multilayer structure comprising at least one continuous inner paper layer sandwiched between at least one continuous top plastic inner liner and at least one continuous bottom plastic inner liner,

-a multilayer structure comprising at least one continuous inner cardboard layer sandwiched between at least one continuous top plastic liner and at least one continuous bottom plastic liner.

In a 49 th aspect according to any one of the 36 th to 48 th aspects, the plastic film exhibits a thickness comprised between 20 and 200 microns.

In a 50 th aspect according to any of the preceding aspects, the plastic film exhibits a free shrinkage (ASTM D2732) at 160 ℃ in both the machine direction and the cross direction that is greater than 3% and less than 20%.

In a 51 st aspect according to any one of the preceding aspects, the plastic film exhibits a free shrinkage (ASTM D2732) at 160 ℃ in both the machine direction and the cross direction which is greater than 3% and less than 15%.

In a 52 th aspect according to any of the preceding aspects, the plastic film exhibits a free shrinkage (ASTM D2732) at 160 ℃ in both the machine direction and the cross direction that is greater than 3% and less than 10%.

In a 53 th aspect according to any one of the preceding aspects, the plastic film exhibits a residual shrink tension in both the machine direction and the transverse direction at 5 ℃, which is at least 3 times greater than the residual shrink tension at 100 ℃. Note that the residual shrinkage tension is determined by the process disclosed in the detailed description.

In a 54 th aspect according to any one of the preceding aspects, the plastic film exhibits a residual shrink tension in both the machine direction and the cross direction at 5 ℃, which is at least 5 times greater than the residual shrink tension at 100 ℃. Note that the residual shrinkage tension is determined by the process disclosed in the detailed description.

In a 55 th aspect according to any one of the 36 th to 54 th aspects, each of the one or more supports (2) presents a through hole, and during gas extraction, at least a portion of the extracted gas passes through the one or more through holes present in the support (2).

In a 56 th aspect according to any one of the 36 th to 55 th aspects, the apparatus of the 35 th aspect is used, each of the one or more supports (2) exhibiting through-holes, and the conveyor comprising a conveyor belt having gas channels and/or porous portions, wherein, during gas extraction, the extracted gas passes through the one or more through-holes present in the support (2) and through the one or more channels or gas permeable portions of the conveyor belt.

A57 th aspect relates to a vacuum skin package comprising:

-a support (2) containing the product,

-a portion (4 a) of plastic film heat-sealed to the top surface of the support (2) containing the product not covered by the product,

wherein the support (2) presents:

a sheet body having a top surface (90), a bottom surface (91) and a thickness (92),

-one or more elongated ridges (93) protruding from the top surface (90), and

-one or more elongated indentations (94) on the bottom surface (91) extending along and corresponding to the elongated ridge (93).

In aspect 58 according to the preceding aspect, the top surface (90) and the bottom surface (91) of the sheet body are flat without the elongated ridges and the elongated indentations and extend along respective parallel top and bottom planes (95, 96).

In a 59 th aspect according to any one of the two preceding aspects, each of the elongate ridges (93) projects above the top plane to define a ridge height (h') comprised between 0.1 and 2.0 mm.

In a 60 th aspect according to any one of the preceding three aspects, each of the elongate ridges exhibits a rounded top profile in cross-section.

In aspect 61 according to any one of the preceding four aspects, each of the elongate ridges (93) has a length measured along the elongate ridge (93) and parallel to the top plane (95) that is at least 10 times the width of the elongate ridge.

In a 62 nd aspect according to any one of the preceding five aspects, the elongate ridge (93) and the corresponding elongate indentation (94) comprise: a first elongate ridge and a corresponding first elongate indentation extending across the support (2) in a first direction; and a second elongate ridge and a corresponding second elongate indentation extending across the support (2) along a second direction transverse, optionally perpendicular, to the first direction.

In a 63 rd aspect according to any one of the preceding six aspects, the support (2) is rectangular and each of the elongate ridges (93) is in the form of a continuous rib extending across the support and having a length which is at least 75% of the length of the longest side of the support.

In a 64 th aspect according to any one of the preceding seven aspects, the support (2) is rectangular and each of the elongate ridges (93) is in the form of a continuous and straight rib extending across the support and having a length which is at least 75% of the length of the longest edge of the support.

In a 65 th aspect according to any one of the preceding eight aspects, the support (2) is rectangular and each of the elongate ridges (93) is in the form of a continuous rib extending across the support and having a length which is at least 90% of the length of the longest edge of the support.

In a 66 th aspect according to any one of the preceding nine aspects, the support (2) is rectangular and each of the elongate ridges (93) is in the form of a continuous and straight rib extending across the support and having a length which is at least 90% of the length of the longest edge of the support.

In a 67 th aspect according to any one of the 57 th to 62 th aspects, the support (2) is circular and each of the elongate ridges (93) is in the form of a continuous rib extending across the support and having a length that is at least 75% of the length of the support diameter.

In a 68 th aspect according to any one of the 57 th to 62 th aspects, the support (2) is circular and each of the elongate ridges (93) is in the form of a continuous and straight rib extending across the support and having a length that is at least 75% of the length of the support diameter.

In a 69 th aspect according to any one of the 57 th to 62 th aspects, the support (2) is circular and each of the elongate ridges (93) is in the form of a continuous rib extending across the support and having a length that is at least 90% of the length of the support diameter.

In a 70 th aspect according to any one of the 57 th to 62 th aspects, the support (2) is circular and each of the elongate ridges (93) is in the form of a continuous and straight rib extending across the support and having a length that is at least 90% of the length of the support diameter.

In a 71 th aspect according to any one of the 57 th to 70 th aspects, the one or more elongated ridges (93) and the elongated indentations (94) are symmetrically positioned with respect to the symmetry axis of the support (2) and present respective portions extending in correspondence with the peripheral annular band of the support.

In the 72 th aspect according to any one of the 57 th to 71 th aspects, the plastic film portion (4 a) heat-sealed to the product-containing support (2) and the product-containing support (2) are made of respective different materials.

In a 73 th aspect according to any one of the 57 th to 72 th aspects, the support (2) presents a thickness comprised between 0.10 mm and 2.00 mm.

In a 74 th aspect according to any one of the 57 th to 73 th aspects, the support (2) is formed by one of:

-a sheet of paper,

-a sheet of paperboard,

-a multi-layer structure comprising a plurality of paper layers,

-a multilayer structure comprising a plurality of paperboard layers,

-a sheet of plastic material,

-a multilayer structure comprising a plurality of plastic layers,

-a multilayer structure comprising at least one continuous inner cardboard layer sandwiched between at least one continuous top plastic liner and at least one continuous bottom plastic liner,

in a 75 th aspect according to any one of the 57 th to 74 th aspects, the plastic film portion (4 a) exhibits a thickness comprised between 20 and 200 microns.

In a 76 th aspect according to any one of the 57 th to 75 th aspects, the coefficient of linear expansion per ° C of the plastic film portion (4 a) in at least one direction is greater than the coefficient of linear expansion per ° C in the same direction of the underlying support (2) at atmospheric pressure and at least in the interval between 20 ℃ and 100 ℃.

In a 77 th aspect according to any one of the 57 th to 76 th aspects, the plastic film portion (4 a) of the support (2) is characterized by a free shrinkage at 160 ℃ in both longitudinal and transverse directions (ASTM D2732) which is greater than 3% and less than 20%, preferably less than 15%, even more preferably less than 10%.

In a 78 th aspect according to any one of the aspects from 57 to 77, the support (2) has a residual shrinkage tension in both the longitudinal and transverse directions determined by the process disclosed in the detailed description, said residual shrinkage tension at 5 ℃ being at least 3 times greater, optionally at least 5 times greater, than the residual shrinkage tension at 100 ℃.

A 79 th aspect relates to an apparatus for packaging products arranged on a support (2), comprising:

-a film supply assembly (3) configured for supplying a plastic film (4);

-an upper tool (10) operating above the base means (6) and configured for holding a film portion (4 a) of said plastic film (4) above said at least one product-containing support (2) positioned in the respective receiving area, the upper tool (10) and the base means (6) being configured to cooperate for heat-sealing the film portion (4 a) to said at least one product-containing support (2),

wherein each receiving area (8) comprises:

-a flat portion (80) extending on a predetermined positioning plane (81) and defining a majority of the surface of the receiving area (8), and

-one or more elongated features (82) having an active surface extending out of the plane of positioning of the flat portion (80).

In an 80 th aspect according to the 79 th aspect, the one or more elongate features comprise a continuous rib extending across the respective receiving area above the locating plane.

In an 81 th aspect according to any one of the two preceding aspects, the one or more elongate features comprise a continuous body extending above or below the positioning plane at a periphery of the respective receiving area.

In an 82 nd aspect according to any one of the preceding three aspects, each of the one or more elongate features extends along a respective preferential development ideal line.

In an 83 th aspect according to the preceding aspects, each of the one or more elongate features extends along a respective preferential development ideal line and has a length (l) measured along the preferential development ideal line, a height (h) relative to the location plane (81) measured perpendicular to the location plane (81), and a width (w) measured parallel to the location plane and perpendicular to the preferential development ideal line.

In an 84 th aspect according to the preceding aspect, the length (l) of each elongate feature is at least 2 times the width (w).

In an 85 th aspect according to any one of the preceding two aspects, the width (w) of each elongate feature is at least 50% of the height (h).

In an 86 th aspect according to any one of the preceding three aspects, the height (h) of each elongate feature is less than 10 mm.

In an 87 th aspect according to any one of the preceding four aspects, the length (l) of each of the elongate features (82) is 5 times or more the width (w) of the elongate feature.

In an 88 th aspect according to any one of the preceding five aspects, the width (w) of each of the elongate features (82) is equal to or greater than the height (h) of the elongate feature.

In an 89 th aspect according to any one of the preceding six aspects, the height (h) of each of the elongate features (82) is comprised between 0.1 and 5 mm.

In a 90 th aspect according to any one of the preceding seven aspects, the width of each of the elongate features (82) is comprised between 0.1 and 30 mm.

In a 91 st aspect according to any one of the preceding eight aspects, the one or more elongate features (82) comprise a plurality of elongate features (82) symmetrically positioned with respect to an axis of symmetry of the receiving area.

In a 92 th aspect according to any one of the preceding nine aspects, the elongate feature (82) comprises:

-one or more first elongate features (83) extending along a first direction,

-one or more second elongate features (84) extending along a second direction at an angle to the first direction.

In a 93 th aspect according to the preceding aspects, the elongate feature further comprises a third elongate feature (85) extending transverse to both the first and second elongate features.

In a 94 th aspect according to any one of the aspects from 79 to 93, the elongate features (82) comprise elongate features (82) extending in correspondence with a peripheral band surrounding a central region of the respective receiving area (8), and/or wherein the elongate features (82) comprise at least one elongate feature of annular shape extending along the peripheral band.

In a 95 th aspect according to any one of the 79 th to 94 th aspects, the one or more elongate features (82) comprise a plurality of non-parallel continuous ribs, optionally a plurality of non-parallel continuous straight ribs, extending at least across the respective receiving area (8) above the positioning plane.

In a 96 th aspect according to the preceding aspect, each of the receiving areas (8) is substantially in the form of a rectangle, optionally a square, and the length of each of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest side of the rectangle.

In a 97 th aspect according to the 95 th aspect, each of the receiving areas is substantially in the form of an ellipse, optionally a circle, and the length of each of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest axis of the ellipse.

In a 98 th aspect according to any one of the 83 th to 97 th aspects, the one or more elongated features (82) comprise at least one continuous body extending above or below the positioning plane at the periphery of the respective receiving area (8) to a height comprised between 0.1 and 10 mm.

In a 99 th aspect according to any one of the 83 th to 98 th aspects, the one or more elongated features (82) comprise at least one continuous body extending above or below the positioning plane at the periphery of the respective receiving area (8) to a height comprised between 0.1 and 5 mm.

In a 100 th aspect according to any one of the two preceding aspects, the flat portion (80) of each receiving area is completely surrounded by the at least one respective continuous body having an annular shape.

In a 101 th aspect according to the preceding aspect, the continuous body has a substantially rectangular frame shape.

In a 102 th aspect according to any one of the two preceding aspects, the continuous body of annular shape is in close proximity to the peripheral border of the flat portion (80) and presents an upper surface extending on a respective lying plane which is staggered from the positioning plane (81) of the flat portion (80).

In a 103 th aspect according to any one of the preceding five aspects, the continuous body upper surface extends on a lying plane parallel to and below the locating plane (81) of the flat portion (80) between said locating plane of the flat portion and said lying plane of the continuous body upper surface by a distance equal to said height (h).

In a 104 th aspect according to any one of the preceding six aspects, the continuous body upper surface extends on a lying plane above and parallel to the lying plane (81) of the flat portion (80) between said lying plane of the flat portion and said lying plane of the continuous body upper surface by a distance equal to said height (h).

In a 105 th aspect according to the preceding aspect, the continuous body and the flat portion of each receiving area are relatively movable one with respect to the other according to a direction perpendicular to said positioning plane (81) for adjusting said height (h).

In a 106 th aspect according to any one of the 79 th to 105 th aspects, each of the elongate features (82) is defined by a respective elongate element removably engaged to the upper side of the base means (6).

In a 107 th aspect according to any one of the preceding aspects, wherein each of the elongate features (82) exhibits a rounded top profile in cross-section.

In a 108 th aspect according to any one of the preceding aspects, the base means (6) comprises a lower tool (11) cooperating with the upper tool (10) in correspondence with the packaging station (5) of the apparatus, and wherein the upper tool (10) and the lower tool (11) are relatively displaceable between:

In a 109 th aspect according to the preceding aspects, the apparatus comprises:

-a vacuum arrangement (13) configured for removing air at least from the volume between said at least one film portion (4 a) and said one or more product-containing supports (2) located in the packaging station (5);

-suction apertures (18) distributed on the active surface (17) of the upper tool (10) and connected with said vacuum arrangement (13) or auxiliary vacuum arrangement (22);

-a heater (21) configured to heat at least a portion of the upper tool action surface (17);

a control unit (100) configured for controlling the upper tool (10) and the lower tool (11), the heater, the vacuum arrangement and optionally the auxiliary vacuum arrangement,

wherein the control unit (100) is configured to execute the following cycle:

o causing the upper tool (10) and the lower tool (11) to be positioned in a first operating condition,

o in the case where the upper tool (10) and the lower tool (11) are in the first operating condition,

-commanding one of a vacuum arrangement (13) or an auxiliary vacuum arrangement (22) to cause suction of gas through the suction aperture (18) and holding the membrane portion (4 a) against or close to the active surface (17),

-commanding the heater (21) to cause heating of at least a portion of the membrane portion (4 a) held by the upper tool (10),

o causing the upper tool (10) and the lower tool (11) to move to a second operating condition,

o in the case where the upper tool (10) and the lower tool (11) are in the second operating condition,

-commanding a vacuum arrangement (13) to draw gas present between said at least one membrane portion (4 a) and the underlying support (2) containing the product,

-commanding one of the vacuum arrangement (13) or the auxiliary vacuum arrangement (22) to cause the expulsion of gas through the suction orifice for re-evacuation, so as to release the film portion (4 a) from the upper tool (10) active surface and drop the film portion (4 a) onto the support (2) containing the product, the film portion (4 a) being heat-sealed to the upper surface of the support (2) not covered by the product, so as to form at least one vacuum skin-packaged product.

In a 110 th aspect according to the 108 th aspect, the apparatus comprises:

-a conveyor (12) configured for displacing one or more product-filled supports (2) along a predetermined path at least from a product loading station (9) to the packaging station (5);

a control unit (100) configured for controlling the conveyor (12), the upper tool (10) and the lower tool (11), the heater, the vacuum arrangement and optionally the auxiliary vacuum arrangement,

wherein the control unit (100) is configured to execute the following cycle:

-commanding the heater to cause heating of at least a portion of the film portion (4 a) held by the upper tool (10),

-causing a conveyor (12) to position one or more of said product-filled supports (2) on respective receiving areas (8) of a base device (6) below said film portions (4 a) held by an upper tool (10),

-commanding one of the vacuum arrangement (13) or the auxiliary vacuum arrangement (22) to cause the expulsion of gas through the suction orifice (18) for re-evacuation, so as to release the film portion (4 a) from the upper tool (10) active surface and drop the film portion (4 a) onto the support (2) containing the product, the film portion (4 a) being heat-sealed to the upper surface of the support (2) not covered by the product, so as to form at least one vacuum skin-packaged product.

In a 111 th aspect according to the preceding aspect, the receiving area (8) is defined on an upper side of a conveyor (12) configured to traverse the packaging station (5) above the lower tool (11).

In a 112 th aspect according to the 109 th aspect, the receiving area (8) is defined on an upper side of the lower tool (11), which directly faces the upper tool (10).

113 th aspect relates to a process for packaging a product arranged on a support (2) using an apparatus according to any one of the preceding aspects, wherein the process comprises the steps of:

-supplying a plastic film (4) from a film supply assembly (3);

-keeping the film portion (4 a) of the plastic film (4) above said at least one product-containing support (2) positioned in the respective receiving area (8);

The 114 th aspect relates to a process for packaging a product arranged on a support (2) using the apparatus of any of the preceding 109 th or 112 th aspects, wherein the packaging process comprises the steps of:

In a 115 th aspect according to the preceding aspect, wherein, with the upper and lower tools in said second operating condition, in particular during said one or more re-venting and/or gas extraction steps, said one or more supports (2) are pressed against the respective receiving areas (8), causing the formation of elongated structures (93, 99) on the supports (2) which are counter-shaped to the elongated features (82) present on the receiving areas.

In a 116 th aspect according to the preceding aspect, each of said one or more supports (2) presents a sheet body having a top surface, a bottom surface and a thickness, wherein the top and bottom surfaces of the sheet body are flat and extend along respective parallel top and bottom planes, excluding said elongated structure formed during said re-venting and/or gas extraction step.

In a 117 th aspect according to any one of the two preceding aspects, each of the one or more supports (2) has been presented prior to the packaging process:

a sheet body having a top surface, a bottom surface and a thickness,

-one or more preformed elongated structures.

In a 118 th aspect according to the preceding aspect, the top and bottom surfaces of the sheet body are flat without including the elongate formations and extend along respective parallel top and bottom planes.

In a 119 th aspect according to either of the two preceding aspects, the preformed elongate formation of each support (2) is positioned over and engages a corresponding elongate feature (82) present on a respective receiving area defined in the base means (6).

In a 120 th aspect according to any one of the preceding three aspects, each of the pre-formed elongate structures is counter-shaped to a corresponding one of the elongate features.

In a 121 th aspect according to any one of the 113 th to 120 th aspects, the plastic film heat-sealed to the product-containing support (2) and the product-containing support (2) are made of respective different materials.

In a 122 th aspect according to the preceding aspect, the coefficient of linear expansion per degree celsius of the plastic film in at least one direction is greater than the coefficient of linear expansion per degree celsius in the same direction of the underlying support (2) at atmospheric pressure and at least in the interval between 20 ℃ and 100 ℃.

In a 123 th aspect according to any one of the preceding 113 th to 122 th aspects, the support (2) presents a thickness comprised between 0.10 mm and 2.00 mm.

In a 124 th aspect according to any one of the 113 th to 123 th aspects, the support is formed by one of:

-a sheet of paper,

-a sheet of paperboard,

-a multi-layer structure comprising a plurality of paper layers,

-a multilayer structure comprising a plurality of paperboard layers,

-a sheet of plastic material,

-a multilayer structure comprising a plurality of plastic layers,

In a 125 th aspect according to any one of the 113 th to 124 th aspects, the plastic film exhibits a thickness comprised between 20 and 200 microns.

In a 126 th aspect according to any one of the 113 th to 125 th aspects, the plastic film is characterized by:

-free shrinkage at 160 ℃ in both the longitudinal and transverse directions (ASTM D2732) which is greater than 3% and less than 20%, preferably less than 15%, even more preferably less than 10%.

In a 127 th aspect according to any one of the 113 th to 126 th aspects, the plastic film is characterized by:

-a residual shrink tension in both the machine direction and the transverse direction determined by the process disclosed in the detailed description, said residual shrink tension at 5 ℃ being at least 3 times greater than the residual shrink tension at 100 ℃, optionally at least 5 times greater.

In a 128 th aspect according to any one of the 113 th to 127 th aspects, each of the one or more supports (2) presents a through-hole, and wherein during gas extraction at least a part of the extracted gas passes through the one or more through-holes present in the support (2), or wherein each of the one or more supports (2) presents a through-hole, and wherein the conveyor comprises a conveyor belt having gas channels and/or porous portions, and during gas extraction the extracted gas passes through the one or more through-holes present in the support (2) and through the one or more channels or gas permeable portions of the conveyor belt.

The 129 th aspect relates to a vacuum skin package obtained with the process of any of the aforementioned process-related aspects.

In a 130 th aspect according to the preceding aspects, the vacuum skin package comprises:

-a support (2) containing the product,

wherein the support (2) presents:

-one or more elongated structures (93; 99),

wherein the top surface (90) and the bottom surface (91) of the sheet body are flat without the one or more elongated structures (93; 99) and extend along respective parallel top and bottom planes (95; 96),

wherein each of the one or more elongated structures (93; 99) has an active surface extending out of one or both of a top plane (95) and a bottom plane (96).

In a 131 th aspect according to the preceding aspect, the one or more elongated structures (99) comprise a continuous ridge (93) extending across the support (2) above the top plane (95).

In a 132 th aspect according to either of the two preceding aspects, the one or more elongated structures (99) comprise a continuous flange (99) extending at the periphery of the respective support (2) above the top plane (95) or below the top plane (95), optionally below the bottom plane (96).

In a 133 th aspect according to any one of the preceding three aspects, each of the one or more elongate structures extends along a respective preferential development ideal line and has:

-a length (L'), measured along said preferential development ideal line,

-a height (H') relative to the top plane (95), measured perpendicular to the top plane (95),

-a width (W') measured parallel to the top plane and perpendicular to the preferential development ideal line.

In a 134 th aspect according to the preceding aspect, the length (L ') is at least 2 times greater than the width (W').

In a 135 th aspect according to any one of the preceding two aspects, the width (W ') is at least 50% of the height (H').

In a 136 th aspect according to any one of the preceding three aspects, the height (H') is less than 10 mm.

In a 137 th aspect according to any one of the preceding four aspects, the length (L ') of each of the elongated structures (93; 99) is 5 times or more the width (W') of the elongated structure.

In a 138 th aspect according to any one of the preceding five aspects, the width (W ') of each of the elongated structures (93; 99) is equal to or greater than the height (H') of the elongated structure.

In a 139 th aspect according to any of the preceding six aspects, the height (H') of each of the elongated structures (93; 99) is comprised between 0.1 and 5 mm.

In a 140 th aspect according to any one of the preceding seven aspects, the width (W') of each of the elongated structures (93; 99) is comprised between 0.1 and 30 mm.

In a 141 th aspect according to any one of the preceding eight aspects, the elongated structure comprises a continuous rib (93) extending across the support (2) above said top plane (95) and having a width (W') comprised between 0.1 and 10 mm.

In a 142 th aspect according to any one of the preceding nine aspects, the elongated structure comprises a continuous flange (99) extending at the periphery of the respective support (2) below said top plane (95), optionally below said bottom plane (96), and having a width (W') comprised between 5 mm and 30 mm.

In a 143 th aspect according to any one of the preceding ten aspects, the one or more elongated structures (93; 99) are positioned symmetrically with respect to the symmetry axis of the support (2).

In a 144 th aspect according to any one of the preceding eleven aspects, the elongated structure (93; 99) comprises:

one or more first elongated structures extending along a first direction,

-one or more second elongated structures extending along a second direction at an angle to the first direction,

-optionally a third elongate structure extending transverse to both the first and second elongate features.

In a 145 th aspect according to any one of the twelve preceding aspects, the elongate structure (93; 99) comprises an elongate structure extending in correspondence with a peripheral band, the peripheral band surrounding a central region of the support (2).

In a 146 th aspect according to any one of the preceding thirteen aspects, wherein the elongated structure (93; 99) comprises at least one elongated structure of annular shape extending along the peripheral band.

In a 147 th aspect according to any of the preceding fourteen aspects, the one or more elongate structures (93) comprise a plurality of non-parallel continuous ribs, optionally a plurality of non-parallel continuous straight ribs, extending at least across the support (2) above the top plane (95).

In a 148 th aspect according to the preceding aspect, each of the supports is substantially in the form of a rectangle, optionally a square, and the length of each of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest side of the rectangle.

In a 149 th aspect according to any one of the 133 th to 147 th aspects, each of the supports (2) is substantially in the form of an ellipse, optionally a circle, and the length of each of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest axis of the ellipse.

In a 150 th aspect according to any one of the preceding seventeen aspects, the one or more elongated structures (99) comprise at least one continuous flange extending at the periphery of the support (2) above or below the top plane (95) to a height (H') comprised between 0.1 and 10 mm.

In a 151 th aspect according to any one of the preceding eighteenth aspects, the one or more elongated structures (99) comprise at least one continuous flange extending at the periphery of the support (2) above or below the top plane (95) to a height (H') comprised between 0.1 and 5 mm.

In aspect 152 according to either of the two preceding aspects, the at least one continuous flange completely surrounds a central portion of the support (2) and has an annular shape.

In a 153 th aspect according to any one of the preceding three aspects, the at least one continuous flange completely surrounds a central portion of the support (2) and has a substantially rectangular frame shape.

In aspect 154 according to any one of the preceding four aspects, the at least one continuous flange completely surrounds a central portion of the support (2) and has a substantially rectangular frame shape, wherein two first opposing rectilinear runs of the continuous flange have a constant width, and wherein two second opposing rectilinear runs perpendicular to the two first opposing rectilinear runs of the continuous flange have a constant width.

In a 155 th aspect according to any one of the five preceding aspects, the flange, in particular a flange having an annular shape, is immediately adjacent to the peripheral boundary of the central portion of the support (2) and presents an upper surface extending on a respective lying plane offset from the top plane of the support.

In a 156 th aspect according to any one of the preceding six aspects, the flange upper surface extends on a lying plane parallel to and below a top plane (95) of the support (2) between said lying plane and the top plane of the upper surface of the flange for a distance equal to said height (H'); or

The upper surface of the flange extends on a lying plane parallel to and above the top plane (95) of the support (2) between said lying plane and the top plane of the upper surface of the flange for a distance equal to said height (H').

In a 157 th aspect according to any one of the preceding aspects from 130 th to the preceding aspects, each of the elongated structures (99) exhibits a circular top profile in cross-section.

In the 158 th aspect from the 130 th to any one of the preceding aspects, the plastic film portion (4 a) heat-sealed to the product-containing support (2) and the product-containing support (2) are made of respective different materials.

In a 159 th aspect according to any of the preceding aspects from 130 to 159 th aspect, the support (2) presents a thickness comprised between 0.10 mm and 2.00 mm.

In a 160 th aspect according to any of the preceding aspects from 130 th to 160 th, the support (2) is formed by one of:

-a sheet of paper,

-a sheet of paperboard,

-a multi-layer structure comprising a plurality of paper layers,

-a multilayer structure comprising a plurality of paperboard layers,

-a sheet of plastic material,

-a multilayer structure comprising a plurality of plastic layers,

In a 161 th aspect according to any one from the 130 th to the preceding aspects, the support (2) plastic film portion (4 a) presents a thickness comprised between 20 and 200 microns.

In a 162 th aspect according to any one of the preceding aspects from 130 th to the preceding aspects, the coefficient of linear expansion per ° C of the plastic film portion (4 a) in at least one direction is greater than the coefficient of linear expansion per ° C in the same direction of the underlying support (2) at atmospheric pressure and at least in the interval between 20 ℃ and 100 ℃.

In a 163 th aspect according to any one of the preceding aspects from 130 th to 163 th, the plastic film portion (4 a) is characterized by:

-free shrinkage at 160 ℃ in both the longitudinal and transverse directions (ASTM D2732) of more than 3% and less than 20%, preferably less than 15%, even more preferably less than 10%; and/or

In a 164 th aspect according to any of the preceding aspects from 130 to 164 th, the height (H') of the elongated structure, in particular the height of the one or more continuous ribs and/or the height of the continuous flange is lower than 5 times the thickness of the support (2), optionally lower than 3 times the thickness of the support (2).

Drawings

The present invention will become more apparent upon reading the following detailed description, given by way of example and not limitation, and which is to be read with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic view of an apparatus for vacuum skin packaging of a product, wherein a packaging station places upper and lower tools in a first operating condition;

fig. 2 is a schematic view of the apparatus of fig. 1 in a subsequent stage of the packaging cycle, wherein the upper tool and the lower tool are in a first operating condition;

fig. 3 is a schematic view of the apparatus of fig. 1 and 2 in a stage of the packaging cycle which follows the stage of fig. 2 and in which the upper and lower tools are in a second operating condition;

FIG. 4 is a schematic view of the apparatus of FIGS. 1-3 in a stage of the packaging cycle subsequent to that of FIG. 3, wherein the upper and lower tools are in a second operating condition;

FIG. 5 is a schematic view of an additional apparatus for vacuum skin packaging of products using a conveyor, particularly an endless conveyor belt, passing through an upper tool and a lower tool;

FIG. 6 is a schematic view of a variation of the apparatus of FIG. 5, which also uses a conveyor, in particular a loop conveyor belt, passing through an upper tool and a lower tool;

FIG. 7 is a schematic view of a detail of a packaging station such as may be used in an apparatus of the type of FIG. 1, wherein the upper and lower tools are in a first operating condition, wherein the packaging station configures the upper and lower tools for forming a plurality of packages per packaging cycle;

FIG. 8 is a schematic view of a detail of the packaging station of FIG. 7 with the upper and lower tools in a second operating condition;

figure 9 shows a top view of a portion of the upper side of a base device usable in the apparatus of any one of the preceding figures, wherein one receiving area for a support filled with a product is defined; in fig. 9, the receiving area includes raised elongate features positioned according to a first pattern;

FIG. 10 is a cross-section along the plane X-X of FIG. 9;

fig. 11 shows a top view of a portion of the upper side of a base device usable in the apparatus of any of fig. 1-8, wherein one receiving area for a support filled with a product is defined; in fig. 11, the receiving area includes raised elongate features positioned according to a second pattern;

FIG. 12 is a cross-section along plane XII-XII of FIG. 11;

FIG. 13 is a top view of a vacuum skin package obtainable using the apparatus of the preceding figures;

FIG. 14 is a cross-section according to plane XIV-XIV of FIG. 13;

fig. 15 shows a top view of a portion of the upper side of a base device usable in the apparatus of any of fig. 1-8, wherein one receiving area for a support filled with a product is defined; in fig. 15, the receiving region includes a raised straight feature located corresponding to the central region of the receiving region, and an annular feature in the form of a positive or negative annular step located peripherally relative to the central region;

figures 16A and 16B show cross-sections along the plane XVI-XVI of figure 15, respectively, in the case of a receiving area having a positive annular step and in the case of a receiving area having a negative annular step surrounding the central area;

FIG. 17 is a cross-sectional view of a vacuum skin package obtainable with the apparatus of the preceding figures, particularly using the base device of FIG. 16A;

FIG. 18 is a cross-sectional view of a vacuum skin package obtainable with the apparatus of the preceding figures, particularly using the base device of FIG. 16B; and

figure 19 is a schematic view of an apparatus for vacuum skin packaging of a product, wherein the packaging station places the upper and lower tools in a first operating condition, and wherein the base device is of the type shown in figure 16B.

Detailed Description

Definition and engagement

The same reference numerals are used to designate corresponding parts or components in the drawings. The figures may not be to scale and so the parts and components shown therein are schematic representations.

In the following description and claims, the apparatus and process refer to the packaging of products on a support or on a support part: the product may or may not be a food product.

By 'vacuum skin packaging' it is intended any packaging process in which a product is placed on a support or support portion and a film of plastic material is applied over the support containing the product, wherein air between the support and the plastic film is evacuated to cause the plastic film to drip onto the product and seal to the surface of the support, thus forming a tight skin on the product and on the support.

When describing each receiving area 8 of the base device 6, it is stated that the receiving area has a flat portion 80 extending on a predetermined positioning plane 81: this means that the flat portion is a flat surface portion of the ideal positioning plane 81.

Each receiving area has one or more elongate features 82 having an active surface extending out of the location plane 81, which means that at least a portion of the elongate feature surface is not part of the location plane, but rather protrudes above or below the location plane 81.

The preferred development of the elongate features is the ideal line (i) along which each feature extends parallel to the orientation plane 81: the ideal line (i) may be a straight line, a series of connected straight lines, a curved line, a circular line formed by straight line segments or a curved line or a combination thereof.

By elongate feature it is meant any configuration of the base means 6 (configured to be in contact with the support 2) having a length (l) significantly greater than a width (w), wherein the length and width are as indicated below and measured as represented in the figures.

The geometry of each elongate feature is defined by:

-a length (l) measured along a preferential development ideal line (i) of each elongated feature,

-a height (h) measured with respect to the positioning plane 81 and perpendicular to the positioning plane 81; note that the height may measure a distance above or below the positioning plane (and thus may measure a positive or negative height relative to plane 81);

-a width (w) measured parallel to the positioning plane and perpendicular to the preferential development ideal line (i).

The preferred development ideal line (I') of the

elongated structures

93, 99 present on the support 2 is the median line along which each structure extends parallel to the top plane 95 along which most of the top surface 90 of each support extends. The ideal line (I') may also be a straight line, a series of connected straight lines, a curved line, a circular line formed by straight or curved lines or a combination thereof.

By elongate structure it is meant any configuration on the support 2 having a length (L ') significantly greater than a width (W'), wherein length and width are as indicated herein below and measured as represented in the drawings. Each elongated structure of the support 2 extends along a respective preferential development ideal line (I'), and the geometry of each

elongated structure

93, 99 on the support 2 is defined by:

-a length (L') measured along said preferential development ideal line (Γ);

-a height (H') relative to the top plane 95, measured perpendicular to the top plane 95; the height H' may be measured as a distance above or below a reference plane, in this case the top plane 95 of the support 2;

Support 2

As used herein, a support means any discrete semi-rigid or flexible structure designed for holding a product to be packaged, such as, for example, a plate or tray, which may have a rectangular shape or any other suitable shape, such as circular, square, oval, etc. In a possible currently preferred embodiment, the support may be a discrete flat element of uniform thickness.

Support may also mean a longitudinal track of continuous support of semi-rigid or flexible construction. Each support portion of the continuous support film is designed to hold a product to be packaged and may be flat and of uniform thickness.

The discrete support or continuous support may be made of a material such as plastic, cardboard, paper, wood, or a combination of the mentioned materials. The discrete support or continuous support may be a single layer or a multi-layer support.

Discrete or continuous plastic supports may be manufactured by thermoforming or injection molding or cutting from foil material. Discrete or continuous paper or cardboard or wood supports may be obtained by cutting or die-cutting from foil material.

The discrete support or the continuous support may comprise through holes. The through holes may be obtained during the manufacturing of the discrete support or in a second stage, for example using a suitable perforation tool part of the packaging device. The through holes in the continuous support are preferably made using a hole making device that is part of the packaging plant or operates upstream of the packaging plant.

The discrete support or continuous support presents a bottom wall having a dimension (i.e., thickness) that is significantly smaller than the other two dimensions.

In those cases where the support presents through holes, these form through channels that span the entire thickness of the bottom wall of the support.

Each support 2 has a top surface 90 and a bottom surface 91 which are flat without the one or more

elongated structures

93, 99 and which extend along respective parallel top and

bottom planes

95, 96.

Membranes or membrane materials applied to supports or support sections

Although most aspects of the invention are applicable to any type of package obtained by applying a plastic film to a support, a currently preferred application of the invention is for making vacuum skin packages. The film or film material that is heat sealed to the support or support portion in vacuum skin applications may be made of a flexible multilayer material that includes at least a first heat-sealable outer layer, an optional gas barrier layer, and a second heat-resistant outer layer. The heat-sealable outer layer may comprise a polymer capable of being welded to the inner surface of the support or supporting portion carrying the product to be packaged, such as, for example, ethylene homopolymers or copolymers (such as LDPE, ethylene/alpha-olefin copolymers, ethylene/acrylic acid copolymers, ethylene/methacrylic acid copolymers and ethylene/vinyl acetate copolymers), ionomers, copolyesters (e.g., PETG). The optional gas barrier layer preferably comprises an oxygen-impermeable resin such as PVDC, EVOH, polyamide and blends of EVOH and polyamide. The heat resistant outer layer may be made of ethylene homo-or copolymers, ethylene/cyclic olefin copolymers (such as ethylene/norbornene copolymers), propylene homo-or copolymers, ionomers, (co) polyesters, (co) polyamides. The film may also include other layers, such as adhesion layers or body layers (bulk layers), to increase the thickness of the film and improve its abuse (abuse) and deep draw properties. Particularly useful body layers are ionomers, ethylene/vinyl acetate copolymers, polyamides, and polyesters. In all film layers, the polymer component may contain suitable amounts of additives typically included in such ingredients. Some of these additives are preferably included in the outer layer or one of the outer layers, while some other additives are preferably added to the inner layer. These additives include slip and antiblock agents (such as talc, waxes, silica, and the like), antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, crosslinking inhibitors, crosslinking enhancers, UV absorbers, odor absorbers, oxygen scavengers, bactericides, antistatic agents, and the like additives known to those skilled in the art of packaging films.

One or more layers of the film may be crosslinked to improve the strength of the film and/or its heat resistance. Crosslinking may be achieved by using chemical additives or by subjecting the film layer to energy radiation. Films for skin packaging are typically manufactured to exhibit low shrinkage when heated during the packaging cycle. Those films typically shrink at 160 ℃ in both the machine and transverse directions (ASTM D2732) by less than 15%, more often by less than 10%, even more often by less than 8%. The film typically has a thickness comprised between 20 and 200 microns, more often between 40 and 180 microns, and even more often between 50 and 150 microns.

Definition and convention regarding materials

PVDC is any vinylidene chloride copolymer wherein the major amount of the copolymer comprises vinylidene chloride and minor amounts of the copolymer comprise one or more unsaturated monomers copolymerizable therewith, typically vinyl chloride and alkyl acrylates or methacrylates (e.g., methyl acrylate or methacrylate) and blends thereof in varying proportions. Typically, the PVDC barrier layer will comprise a plasticizer and/or a stabilizer as known in the art.

As used herein, the term EVOH includes saponified or hydrolyzed ethylene-vinyl acetate copolymers and refers to ethylene/vinyl alcohol copolymers having an ethylene comonomer content preferably comprising from about 28 to about 48 mol%, more preferably from about 32 to about 44 mol% of ethylene, and even more preferably a degree of saponification of at least 85%, preferably at least 90%

The term "polyamide" as used herein is intended to refer to both homopolyamides and copolyamides or terpolyamides. The term specifically includes aliphatic polyamides or copolyamides, such as polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 69, polyamide 610, polyamide 612, copolyamide 6/9, copolyamide 6/10, copolyamide 6/12, copolyamide 6/66, copolyamide 6/69; aromatic and partially aromatic polyamides or copolyamides such as polyamide 6I, polyamide 6I/6T, polyamide MXD6, polyamide MXD 6/MXDI; and blends thereof.

As used herein, the term "copolymer" refers to a polymer derived from two or more types of monomers, and includes terpolymers. Ethylene homopolymers include High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE). Ethylene copolymers include ethylene/alpha-olefin copolymers and ethylene/unsaturated ester copolymers. Ethylene/α -olefin copolymers typically include copolymers of ethylene and one or more comonomers selected from α -olefins having from 3 to 20 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, and the like.

The ethylene/alpha-olefin copolymer typically has a molecular weight in the range of from about 0.86 g/cm³To about 0.94 g/cm³Density in the range of (1). The term Linear Low Density Polyethylene (LLDPE) is generally understood to include those falling within about 0.915 g/cm³To about 0.94 g/cm³And in particular about 0.915 g/cm³To about 0.925 g/cm³Of ethylene/alpha-olefin copolymers in the density range of (a). Sometimes, from about 0.926 g/cm³To about 0.94 g/cm³Linear polyethylene in the density range of (a) is referred to as Linear Medium Density Polyethylene (LMDPE). Low density ethylene/alpha-olefin copolymers may be referred to as Very Low Density Polyethylene (VLDPE) and Ultra Low Density Polyethylene (ULDPE). The ethylene/alpha-olefin copolymer may be obtained by either a heterogeneous or homogeneous polymerization process.

Another useful ethylene copolymer is an ethylene/unsaturated ester copolymer, which is a copolymer of ethylene and one or more unsaturated ester monomers. Useful unsaturated esters include: vinyl esters of aliphatic carboxylic acids, wherein the esters have from 4 to 12 carbon atoms, such as vinyl acetate; and alkyl esters of acrylic or methacrylic acid, wherein the esters have from 4 to 12 carbon atoms.

Ionomers are copolymers of ethylene and an unsaturated monocarboxylic acid having a carboxylic acid neutralized with a metal ion such as zinc or preferably sodium.

Useful propylene copolymers include: propylene/ethylene copolymers, which are copolymers of propylene and ethylene having a large weight percent content of propylene; and propylene/ethylene/butene terpolymers, which are copolymers of propylene, ethylene and 1-butene.

As used herein, the term "polyolefin" refers to any polymeric olefin, which can be linear, branched, cyclic, aliphatic, aromatic, substituted, or unsubstituted. More specifically, included within the term polyolefin are homopolymers of olefins, copolymers of olefins and non-olefinic comonomers copolymerizable with olefins (such as vinyl monomers), modified polymers thereof, and the like. Specific examples include polyethylene homopolymers, polypropylene homopolymers, polybutylene homopolymers, ethylene- α -olefin copolymers, propylene- α -olefin copolymers, butene- α -olefin copolymers, ethylene-unsaturated ester copolymers, ethylene-unsaturated acid copolymers (e.g., ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-acrylic acid copolymers, and ethylene-methacrylic acid copolymers), ethylene-vinyl acetate copolymers, ionomer resins, polymethylpentene, and the like.

The term "polyester" is used herein to refer to both homopolyesters and copolyesters, wherein a homopolyester is defined as a polymer obtained from the condensation of a dicarboxylic acid and a diol, and a copolyester is defined as a polymer obtained from the condensation of one or more dicarboxylic acids and one or more diols. Suitable polyester resins are, for example, polyesters of ethylene glycol and terephthalic acid (i.e., polyethylene terephthalate (PET)). Preferred are polyesters comprising ethylene units and comprising at least 90 mole%, more preferably at least 95 mole%, terephthalate units based on dicarboxylic acid units. The remaining monomer units are selected from other dicarboxylic acids or diols. Suitable further aromatic dicarboxylic acids are preferably isophthalic acid, phthalic acid, 2,5-, 2, 6-or 2, 7-naphthalenedicarboxylic acid. As the alicyclic dicarboxylic acid, cyclohexane dicarboxylic acid (particularly, cyclohexane-1, 4-dicarboxylic acid) should be mentioned. With regard to the aliphatic dicarboxylic acids, the (C3-Ci9) alkanedioic acids are particularly suitable, in particular succinic acid, sebacic acid, adipic acid, azelaic acid, suberic acid or pimelic acid. Suitable diols are, for example: aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, 1, 5-pentanediol, 2-dimethyl-1, 3-propanediol, neopentyl glycol and 1, 6-hexanediol; and cycloaliphatic diols such as 1, 4-cyclohexanedimethanol and 1, 4-cyclohexanediol, optionally heteroatom-containing diols having one or more rings.

Copolyester resins derived from one or more dicarboxylic acids or diesters of lower alkyl groups (up to 14 carbon atoms) thereof with one or more diols (particularly, aliphatic or alicyclic diols) may also be used as the polyester resin for the base film. Suitable dicarboxylic acids include: aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid or 2,5-, 2, 6-or 2, 7-naphthalenedicarboxylic acid; and aliphatic dicarboxylic acids such as succinic acid, sebacic acid, adipic acid, azelaic acid, suberic acid, or pimelic acid. Suitable diol(s) include: aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, 1, 5-pentanediol, 2-dimethyl-1, 3-propanediol, neopentyl glycol and 1, 6-hexanediol; and alicyclic diols such as 1, 4-cyclohexanedimethanol and 1, 4-cyclohexanediol. Examples of such copolyesters are (i) copolyesters of azelaic acid and terephthalic acid with an aliphatic diol (preferably ethylene glycol); (ii) copolyesters of adipic acid and terephthalic acid with an aliphatic diol (preferably ethylene glycol); and (iii) copolyesters of sebacic acid and terephthalic acid with an aliphatic diol (preferably, butanediol); (iv) copolyesters of ethylene glycol, terephthalic acid and isophthalic acid. Suitable amorphous copolyesters are those derived from aliphatic and cycloaliphatic diols with one or more dicarboxylic acids, preferably aromatic dicarboxylic acids. Typical amorphous copolyesters include copolyesters of terephthalic acid with aliphatic and cycloaliphatic diols, especially ethylene glycol and 1, 4-cyclohexanedimethanol.

Detailed Description

The drawings illustrate exemplary aspects of several embodiments of the invention.

Referring to fig. 1-4 and 19, reference numeral 1 designates an apparatus for packaging products. In more detail, the apparatus 1 provides for packaging the products P arranged on the support 2. The apparatus comprises a film supply assembly 3 configured for supplying a plastic film 4 to a packaging station 5 defined by the apparatus 1, as described herein below. The apparatus 1 further comprises a base device 6 having an upper side 7 defining one or more receiving areas 8, each designed for receiving a respective support 2. Since the support is typically a planar body, the receiving area 8 is defined by an indentation or seat on the upper side 7 of the base means, which indentation or seat is configured for receiving the support. Alternatively, the receiving area may be a pre-established area of the upper side of the base device; fig. 9-12 show possible examples of reception areas 8. Each of the receiving areas 8 is configured in particular for receiving at least one respective product-filled support 2, i.e. a support carrying a respective product P, on which the product P can be loaded at a product loading station 9.

At the packaging station 5, the apparatus 1 presents an upper tool 10 operating above the base device 6 and configured for holding the film portions 4a of said plastic film 4 above at least one product-containing support 2 positioned in a respective receiving area 8 of the upper side 7 of the base device 6. As shown in fig. 1-4, 19, the upper tool 10 and the base device 6 are configured to cooperate for heat-sealing the film portions 4a to the product-containing support 2, which has reached the packaging station 5 and is positioned on the respective receiving area 8, below and in alignment with the film portions 4 a.

The apparatus 1 further comprises a lower tool 11, which cooperates with the upper tool 10, in correspondence with the packaging station 5; in more detail, the upper tool 10 and the lower tool 11 are relatively displaceable between: a first operating condition (see fig. 1 and 2, fig. 19) in which the upper tool is sufficiently spaced apart from the lower tool to allow positioning of one or more of the supports 2 loaded with product below the film portion 4a held by the upper tool 10; and a second operating condition (see figures 3 and 4) in which the upper tool 10 is approached with respect to the lower tool 11 and is configured to heat-seal said at least one film portion 4a to said at least one underlying support 2 containing the product.

In the example of fig. 1-4 (however, the same is true for the alternative of fig. 19, although only the first operating condition is shown in this case), the upper tool and the lower tool are in gas-tight contact with each other to form a vacuum chamber 12, from which gas is extracted during the vacuum skin packaging process, corresponding to the second operating condition, as will be explained herein below. This feature is an option and may not be present if the apparatus 1 is only designed to heat seal the film portions 4a onto the respective supports to form the lid without creating any vacuum.

In practice, the base device 6 may be very simple and require operator intervention to position the support with the respective product on said receiving area 8. Alternatively, the base device 6 may comprise a conveyor 12 configured for displacing one or more product-filled supports along a predetermined path at least from the product loading station 9 to the packaging station 5: the conveyor may comprise any suitable transfer device; for example, the conveyor may include: a first transfer device (such as a belt, robotized arm, gripper chain, displaceable plate or any other suitable device) which brings the support with the product next to the packaging station; and second transfer means (such as belts, robotized arms, gripper chains, displaceable plates or any other suitable means) which pick up the support 2 loaded with products and position it on a respective receiving area 8 inside the packaging station 5.

In fig. 1-4, 19, an apparatus 1 is disclosed, which is designed to form vacuum skin packages and comprises a vacuum arrangement 13 configured for removing air from at least a volume V between said at least one film portion 4a and said one or more product-containing supports 2 located on said receiving area 8 in the packaging station; as shown in fig. 3, the vacuum arrangement 13 comprises at least one vacuum pump 14, which is connected to the vacuum chamber 12 via a suction line 15. The vacuum pump 14 is operable to draw air via a suction line 15 and thereby remove gas from the vacuum chamber 12 and hence also from the volume V between the membrane portion 4a and the underlying product-containing support 2. The upper tool 10 comprises suction apertures 18 distributed on its active surface 17 opposite to and facing the receiving zone 8. The suction aperture 18 is connected to a vacuum source, which may be the same vacuum arrangement 13 as described above or a dedicated auxiliary vacuum arrangement 22 as shown in fig. 1-4, wherein an auxiliary suction line 19 connects the suction aperture 18 to an auxiliary suction pump 20 of the auxiliary vacuum arrangement 22.

The apparatus further comprises a heater 21 configured to heat at least a portion of the upper tool action surface 17; the heater may be embedded in the upper tool and comprise a heating circuit for heating the active surface, for example using electrical resistance or a thermal fluid. However, it is not excluded that other types of heaters suitable for heating the heating surface may be used, such as infrared lamps or others.

The control unit 100 is connected with and configured to control: conveyor 12 (if present), upper tool 10 and lower tool 11, heater 21, vacuum arrangement 13 and auxiliary vacuum arrangement 22 (if present). The control unit may for example control actuators acting on the conveyor, such as electric motors or fluid actuators, actuators acting on the upper tool and/or the lower tool, such as electric motors or fluid actuators, actuation circuits connected to the heater, pump(s) and/or valve portions of the vacuum arrangement and/or the auxiliary vacuum arrangement.

In more detail, the control unit 100 is configured to perform the following packaging cycle:

first, the control unit 100 commands the appropriate motor(s) and/or actuator(s) and causes the positioning of the upper tool 10 and the lower tool 11 in the first operating condition;

then, with the upper tool 10 and the lower tool 11 in the first operating condition, the control unit 100 commands one of the vacuum arrangement 13 or the auxiliary vacuum arrangement 22 (in fig. 1-4 and 19, the control unit commands the auxiliary vacuum arrangement 22) to cause suction of gas through the suction aperture 18; this allows to keep the film portion 4a against or close to said active surface 17 and above at least one corresponding product-containing support 2 present in the packaging station 5;

the control unit 100 also commands the heater 21 to cause heating of at least a portion (preferably all) of the film portion 4a held by the upper tool; this phase of heating the active surface 17 can start before even putting the upper tool 10 and the lower tool 11 in the first operating condition; alternatively, the heating phase may begin immediately before or while suction is induced through the suction orifice 18; in a further alternative, the control unit 100 may be configured to maintain the temperature of the active surface 17 at a constant temperature selected on the basis of the material forming the film 4 during the entire packaging cycle or sufficient to give the film portion 4a sufficient deformability and adhesiveness;

if the apparatus comprises a conveyor 12, the control unit 100 is further configured (when the upper and lower tools are in the first operating condition) to command the conveyor motor or conveyor actuator to cause the conveyor 12 to position one or more product-laden supports 2 on the respective receiving areas 8 of the base means 6, below the film portions 4a held by the upper tool 10; if the apparatus 1 does not comprise an automatic conveyor, the operator should (when the upper and lower tools are in the first operating condition) position the support 2 loaded with product on the respective receiving area 8 of the base device 6, below the film portion 4a held by the upper tool 10;

the control unit 100 is further configured to subsequently cause the upper tool and the lower tool to move to the second operating condition;

then, with the upper tool 10 and the lower tool 11 in the second operating condition, the control unit 100 commands the vacuum arrangement to extract the gas present in the vacuum chamber 12, and in particular from the volume V between the membrane portion 4a and the underlying support 2 containing the product (see fig. 3 and 4); during this phase, the auxiliary vacuum arrangement (or a designated part of the vacuum arrangement) continues to suck via the suction orifice 18 to keep the membrane portion 4a attached to the upper tool 10 (adsorption);

after a specified time-out time from the extraction of gas from the chamber 12, or once a specified vacuum degree has been reached in said chamber 12, the control unit 100 commands the vacuum arrangement or auxiliary vacuum arrangement to cause the re-evacuation of gas through the suction orifice 18: this causes the release of the film portion from the active surface 17 and, in correspondence with the top surface of the support not covered by the product, allows the film portion to effectively drip and heat seal to the support 8 containing the product to form at least one vacuum skin-packaged product (figure 4); the re-venting stage may include connecting the suction orifice 18 to atmospheric pressure outside the apparatus or pumping air into the line 19 and the orifice 18: in both cases, as a result of the vacuum level reached below the membrane portion 4a and in particular in the volume V, the membrane portion is subjected, at the start of the re-venting phase, to a pressure difference which pushes it downwards against the support 2 containing the product; it should also be noted that in some embodiments, the re-venting phase is only initiated once at least the peripheral strip of the film portion 4a has been heat-sealed to the corresponding peripheral strip of the support 2.

The packaging device 1 shown in fig. 5 comprises the same components as described above, and these components are therefore identified with the same reference numerals as used in fig. 1-4. In detail, the apparatus 1 of fig. 5 comprises a film supply assembly 3 configured for supplying a plastic film 4 to a packaging station 5. The apparatus 1 further comprises a base device 6 having an upper side 7 defining one or more receiving areas 8, each designed for receiving a respective support 2 carrying a respective product, which can be loaded on the support at a product loading station 9. At the packaging station 5, the apparatus 1 presents an upper tool 10 operating above the base device 6 and configured for holding the film portion 4a of the plastic film 4 above said at least one product-containing support 2 positioned in the respective receiving area 8 of the upper side 7 of the base device 6. The upper tool 10 and the base device 6 are configured to cooperate for heat-sealing the film portions 4a to the product-containing support 2, which has arrived at the packaging station 5 and is positioned on the respective receiving area 8, below and in alignment with the film portions 4 a. In the apparatus of fig. 5, a conveyor 12 traverses the packaging station 5 and a receiving area 8 is defined on the upper side of the conveyor. In more detail, the conveyor 12 comprises at least one endless conveyor belt configured so as to have branches that pass constantly through the packaging station above the lower tools 11. In correspondence with the packing station 5, the lower tool 11 cooperates with the upper tool 10 and with the conveyor 12; in more detail, the upper tool 10 and the lower tool 11 are relatively displaceable between: a first operating condition in which the upper tool is sufficiently spaced from the lower tool to allow one or more of the supports 2 containing the product to be positioned below the film portion 4a held by the upper tool 10; and a second operating condition (see figure 5) in which the upper tool 10 is approached with respect to the upper side of the lower tool 11 and of the conveyor 12, to heat-seal said at least one film portion 4a to said at least one underlying support 2 containing the product.

In the example of fig. 5, in correspondence with the second operating condition, the upper tool acts against the upper side of the branch of the conveyor 12 passing through the packaging station (possibly interposing the peripheral border of the film portion 4a, as in the example of fig. 5), while the lower tool acts on the lower side of this branch, so as to form a vacuum chamber 12 from which gas is extracted during the vacuum skin packaging process, as will be explained herein below. This feature of the apparatus of fig. 5 may not be present if the apparatus 1 of fig. 5 is only designed to heat seal the film portions 4a onto the respective supports to form the lids without creating any vacuum.

As mentioned, the base device 6 of the apparatus of fig. 5 comprises a conveyor 12 in the form of an endless conveyor belt configured for displacing one or more product-filled supports 2 along a predetermined path at least from the product loading station 9 to the packaging station 5. The support 2 can be moved on a conveyor from a support store 23 located upstream of the product loading station 9 to the product loading station 9, where it receives the products P and is then guided to a packaging station, where the film portions 4a are applied to form packages 24, which are then moved to a package collecting station 25.

The apparatus 1 of fig. 5 is designed to form vacuum skin packages and comprises a vacuum arrangement 13 configured for removing air at least from the volume V between said at least one film portion 4a and said one or more product-containing supports 2 located on said receiving area 8 in the packaging station; as shown in fig. 3, the vacuum arrangement 13 comprises at least one vacuum pump 14, which is connected to the vacuum chamber 12 via a suction line 15. The vacuum pump 14 is operable to draw air via a suction line 15 and thereby remove gas from the vacuum chamber 12 and hence also from the volume V between the membrane portion 4a and the underlying product-containing support 2.

The upper tool 10 comprises suction apertures 18 distributed on its active surface 17 opposite to and facing the receiving zone 8. The suction aperture 18 is connected to a vacuum source, which may be the same vacuum arrangement 13 described above or a dedicated auxiliary vacuum arrangement 22, wherein an auxiliary suction line 19 connects the suction aperture 18 to an auxiliary suction pump 20 of the auxiliary vacuum arrangement 22.

The apparatus further comprises a heater 21 configured to heat at least a portion of the upper tool action surface 17; the heater may be embedded in the upper tool and comprise a heating circuit for heating the active surface, for example using electrical resistance or a thermal fluid. However, it is not excluded that other types of heaters suitable for heating the heating surface may be used, such as infrared lamps or others. The control unit 100 is connected with and configured to control: conveyor 12, upper tool 10 and lower tool 11, heater 21, vacuum arrangement 13 and auxiliary vacuum arrangement 22 (if present). The control unit 100 may for example control actuators acting on the conveyor, such as electric motors or fluid actuators, actuators acting on the upper tool and/or the lower tool, such as electric motors or fluid actuators, actuation circuits connected to the heater, pump(s) and/or valve portions of the vacuum arrangement and/or the auxiliary vacuum arrangement.

then, with the upper tool 10 and the lower tool 11 in the first operating condition, the control unit 100 commands one of the vacuum arrangement 13 or the auxiliary vacuum arrangement 22 (in fig. 5, the control unit commands the auxiliary vacuum arrangement 22) to cause suction of gas through the suction aperture 18; this allows to keep the film portion 4a against or close to said active surface 17 and above at least one corresponding product-containing support 2 present in the packaging station 5;

the control unit 100 also commands the heater 21 to cause heating of at least a portion (preferably all) of the film portion 4a held by the upper tool 10; this phase of heating the active surface 17 can start before even putting the upper tool 10 and the lower tool 11 in the first operating condition; alternatively, the heating phase may begin immediately before or while suction is induced through the suction orifice 18; in the alternative, the control unit 100 can be configured to maintain the temperature of the active surface 17 at a constant temperature, selected on the basis of the material forming the film 4 during the entire packaging cycle;

the control unit 100 is also configured (when the upper and lower tools are in the first operating condition) to command the conveyor motors or conveyor actuators to cause the conveyor 12 to position one or more product-laden supports 2 on the respective receiving areas 8 of the base device, below the film portions 4a held by the upper tool 10; note that the control unit can also control the product loading station and the support warehouse, so that the whole process is automated by controlling the accumulation (position) of the supports from the warehouse onto the conveyor branches and the subsequent accumulation of the products on the respective supports;

the control unit 100 is further configured to subsequently cause the upper tool and the lower tool to move to the second operating condition; in the example of fig. 5, when the first tool 10 and the second tool 11 reach the second operating condition, the lower tool abuts closely against the lower face of the conveyor, while the upper tool abuts closely against the upper face of the conveyor (at most the film portion 4a is inserted);

then, with the upper and lower tools in the second operating condition, the control unit 100 commands the vacuum arrangement to extract the gas present in the vacuum chamber 12, and in particular from the volume V between the membrane portion 4a and the underlying support 2 containing the product (see fig. 3 and 4); during this phase, the auxiliary vacuum arrangement (or a designated part of the vacuum arrangement) continues to suck via the suction aperture 18 to keep the membrane portion 4a attached to the upper tool 10; note that in the example of fig. 5, the support exhibits through holes that are aligned with corresponding holes or gas permeable portions of the conveyor, so that gas extracted from the volume V passes through the support holes, the conveyor, and is then evacuated.

After a specified time-out time from the extraction of gas from the chamber 12, or once a specified vacuum degree has been reached in said chamber 12, the control unit 100 commands the vacuum arrangement or auxiliary vacuum arrangement to cause the re-evacuation of gas through the suction orifice 18: this causes the release of the film portion from the active surface 17 and, in correspondence with the top surface of the support not covered by the product, allows the film portion to effectively drip and heat seal to the support 8 containing the product to form at least one vacuum skin-packaged product; the re-venting stage may include connecting the suction orifice 18 to atmospheric pressure outside the apparatus or pumping air into the line 19 and the orifice 18: in both cases, as a result of the vacuum level reached below the membrane portion 4a and in particular in the volume V, the membrane portion is subjected, at the start of the re-venting phase, to a pressure difference which pushes it downwards against the support containing the product; it should also be noted that in some embodiments, the re-venting phase is only initiated once at least the peripheral strip of the film portion 4a has been heat-sealed to the corresponding peripheral strip of the support 2.

The apparatus of fig. 6 is very similar to the apparatus of fig. 5: the only difference is that in the apparatus of figure 5 the film 4 is fed as a continuous web by the film supply 9 and then cut by the cutter 26 operating at or downstream of the wrapping station 5, whereas in the apparatus of figure 6 the cutting station 27 acts immediately downstream of the film supply station to form the cut film sheet 4b, which is then displaced into the wrapping station and below the upper tool by means of a swinging platform 28, also controlled by a motor or actuator 29 commanded by the control unit 100.

Fig. 7 and 8 disclose a variant of the packaging station 5 of the apparatus of fig. 1-4 (note that in fig. 7 and 8, identical parts or portions of the apparatus of fig. 1 are identified with the same reference numerals used in fig. 1). According to this variant, the upper tool 10 and the lower tool 11 are designed to receive two adjacent supports 2 containing the product and thus to produce two vacuum skin packages per packaging cycle. Furthermore, the packaging station 5 comprises a clamping device 30, which may be in the form of a frame having a plurality of (in this case two) apertures 31, which are interposed between the upper tool 10 and the lower tool 11 and are controlled so as to clamp the film portions 4a against the periphery 10a of the upper tool 10, to allow air to be sucked through the suction apertures 18 and thus adhere the film portions to the active surface of the upper tool, without the risk that the film portions 4a may slip or be displaced from their correct position during suction and even in the presence of significant deformations imparted to the film. Furthermore, one of the upper tool 10 and the lower tool 11 comprises a cutting device 31: in fig. 7 and 8, the cutting device 31 is housed (host) in the lower tool 11 and comprises at least one vertically oscillating blade which can be controlled so as to cut the film portion 4a to separate the vacuum skin packages once it has been heat-sealed to the underlying support.

Fig. 19 discloses another variant of the packaging station 5 of the apparatus of fig. 1-4. In particular, the packaging station of fig. 19 corresponds to the packaging station of fig. 1-4, but for some details of the base device 6 and the lower tool 11. As shown in fig. 19, a portion of the upper side of the base device 6 defines at least one receiving area for a support (2) containing a product; in the case of fig. 19, the lower tool has a central lower tool and a peripheral lower tool which can be positioned as shown in fig. 19, wherein the top surface of the peripheral lower tool 11a is slightly lower compared to the top surface of the central lower tool 11 b. Alternatively, the top surface of the peripheral lower tool may be slightly higher compared to the top surface of the central lower tool. Fig. 15 shows a top view of a possible receiving area defined by the base device 6 of fig. 19, and fig. 16A and 16B show a cross-section along the plane XVI-XYI of fig. 15 in case the receiving area has a positive annular step (thus using a peripheral lower tool with a slightly higher top surface than the central lower tool) and in case the receiving area has a negative annular step surrounding the central area (thus using a peripheral lower tool with a slightly lower top surface than the central lower tool, as shown in fig. 19), respectively; it is noted that the relative positioning of the peripheral lower tool and the central lower tool may be adjusted by the operator prior to the operation of the packaging apparatus, or it may be automatically controlled by the control unit 100 based on operator input or a pre-stored program, wherein the control unit acts on one or more suitable actuators operating on the base device.

Following the general description of the apparatus of fig. 1-4, 5-6, 7-8, and 19 above, a detailed description of certain novel aspects of the present invention is provided herein below. These novel aspects may be applied to any of the apparatuses described above and shown in fig. 1-8, 9-12, 15, 16A, 16B, and 19.

Reception area 8

According to one aspect, each of the receiving areas 8 defined on top of the base device (on the lower tool upper side (fig. 1-4, 7, 8 and 19)) or on the conveyor upper side (fig. 5 and 6)) comprises: a flat portion 80 extending on a predetermined positioning plane 81 and defining most of the surface of the receiving area 8; and one or more elongate features 82 projecting above the locating plane 81 of the planar portion 80. In other words, each of the receiving areas has a flat surface of at least 75%, preferably greater than 85%, wherein the elongate features are relatively narrow and elongate ribs and represent the only discontinuity in the planarity with the receiving area.

Fig. 9-12 show a part of the upper side 7 of the base means, which may be a part of the top side of the lower tool 11 or a part of the conveyor 12 traversing the packaging station 5. As shown in fig. 9-12, the elongate features 82 may include: one or more first elongate features 83 extending along a first direction; and one or more second elongate features 84 extending along a second direction at an angle to the first direction. For example, the first elongate feature 83 may be a plurality of elongate parallel projections and the second elongate feature 84 may be a plurality of parallel elongate projections directed transverse, optionally perpendicular, to the first elongate feature.

In fig. 9-10, a solution is shown wherein the first elongate feature 83 comprises two elongate parallel projections and the second elongate feature 84 comprises two parallel elongate projections perpendicular to the first elongate feature. In practice, in the example of fig. 9-10, the mentioned first and second

elongated features

83, 84 form annular features surrounding the central zone of the respective receiving area 8; the annular features are positioned in correspondence with the peripheral band of the respective receiving area: in fact, the annular feature is much closer to the edge 8a of the receiving area than to the center of the receiving area and surrounds the central area of the receiving area. In the example of fig. 9-10, there are also two optional additional elongated features 85, symmetrically disposed on the respective receiving areas 8 and each presenting: a main straight portion parallel to one of the first or second elongate features; and a terminal curved portion directed toward the symmetrically opposite additional elongate feature 85.

Note that the elongate feature 82 may also include a third or fourth elongate feature that is directed transverse to the first and second elongate features. In fig. 11 and 12, an example is shown in which a first elongate feature 83 in the form of a straight parallel projection extends parallel to the edge of the receiving area 8a, a second elongate feature 84 in the form of a straight projection extends at an acute angle α to one of the first elongate features, and a third elongate feature 85 in the form of a straight projection extends at an acute angle β to the other of said first elongate features 83, thereby forming a pattern of elongate features that is symmetrical and shaped M when viewed from above.

Entering now into structural details, and referring for example to fig. 9-12, each of the elongate features is in the form of a continuous, optionally straight, rib extending across the respective receiving area.

For example, fig. 9-12 illustrate elongate features in the form of continuous ribs extending across the respective receiving areas above the positioning plane; each of the one or more elongate features extends along a respective preferential development ideal line and is characterized by:

-a length (l) measured along said preferential development ideal line,

a height (h) relative to the positioning plane 81, measured perpendicular to the positioning plane 81,

-a width (w) measured parallel to the positioning plane and perpendicular to the preferential development ideal line.

In the example of fig. 9-12, the length (l) is at least 2 times greater than the width (w), optionally at least 10 times greater, the width (w) is at least 50% of the height (h), and the height (h) is less than 10 mm, and preferably less than 5 mm.

In more detail, the length (l) of each of the elongate features 82 is 5 times or more the width (w), and the width (w) is equal to or greater than the height (h) of the elongate feature. For example, each of the elongate features 82 may be a continuous rib having a height (h) included between 0.1 and 5 mm, a width included between 0.1 and 30 mm, and a length that may be greater than 50 mm.

The receiving areas are generally in the form of rectangles, and each of the elongate features is in the form of a continuous, optionally straight, rib extending across the respective receiving area and having a length which is at least 75%, optionally 90%, of the length of the longest side of the rectangle. If the receiving areas are in the form of ellipses (or circles), each of the elongate features is in the form of a continuous, optionally straight rib extending across the respective receiving area and having a length that is at least 75%, optionally 90%, of the length of the longest axis of the ellipse (or the diameter of the circle).

In one embodiment (see fig. 12), each of the elongate features may be defined by a respective elongate element removably engaged to the upper side of the base device. For example, each of the elongate features may include a respective rod that is removably coupled to the lower tool or conveyor so as to modify the surface thereof as desired. Alternatively (see fig. 10), the lower tool or conveyor may be manufactured with a corresponding top surface having pre-formed elongated features. The elongate features not only serve to form or retain corresponding ridges on the support (as will be apparent from this overall description), but also serve as elements to centre the respective support in position on the receiving area (this may be particularly advantageous when using foraminous supports having through-holes which need to be aligned with corresponding gas suction passages (channels) on the conveyor 12 or in the lower tool 11).

In a possible variant, each of the elongate features projects above the locating plane 81 to define a feature height h (see fig. 10, 12) above the locating plane to be comprised between 0.1 and 2.0 mm in other words, each of the receiving areas may be substantially flat, with elongate features representing only elongate and narrow ribs that are slightly exposed above the predominantly flat top surface of the receiving area.

Additionally, according to a further aspect, each of the elongate features exhibits a rounded top profile in cross-section. This allows avoiding any possibility of cutting or ripping the support during the packaging cycle.

As shown in the embodiments described above, a currently preferred solution is to employ elongate features that are symmetrically positioned with respect to the longitudinal axis of symmetry of the receiving area, the elongate features forming a pattern on the receiving area.

Referring now to the example of fig. 15, 16A and 16B, the one or more elongate features 82 include a continuous body 88 that extends at the periphery of the respective receiving area, forming a planar surface that is positioned above (fig. 16A) or below (fig. 16B) the positioning plane. The height h relative to the positioning plane 81 is comprised between 0.1 and 10 mm, optionally between 0.1 and 5 mm, above or below the plane 81. In a currently preferred embodiment, the continuous body forms a flat surface at a height of about 0.1 to 2 mm below the locating plane. As shown in fig. 15, the receiving area may also include elongate features in the form of continuous ribs of the type described above in connection with fig. 9-12.

Returning to the continuous body 88, the flat portion 80 of each receiving area is completely surrounded by a respective continuous body having an annular shape: in particular, fig. 15 shows a substantially rectangular frame-shaped continuous body. The continuous body 88 of annular shape is immediately adjacent to the peripheral border of the flat portion 80 and presents an upper surface extending on a respective lying plane 89 staggered from the positioning plane 81 of the flat portion 80, wherein the distance between said positioning plane of the flat portion and said lying plane of the upper surface of the continuous body is equal to the height h, as shown in fig. 16A and 16.

It is noted that the base means 6 can be designed such that the continuous body and the flat portion of each receiving area are relatively movable one with respect to the other according to a direction perpendicular to said positioning plane 81 for adjusting said height h.

Support 2

Each of said one or more supports 2 presents a sheet body having a top surface 90, a bottom surface 91 and a thickness 92; one or more elongated structures 99 may be preformed on the support.

Alternatively, the support 2 may initially be completely flat, and then when the packaging cycle is conducted, the flat support is pushed against the top surface of the conveyor or lower tool (this is done during the re-venting phase in the vacuum skin packaging cycle, as explained above). The pressure and heat forms and forces the support 2 to take the same shape as the underlying receiving area 8, thus providing the initially flat support with an elongated structure 93 and/or 99 that is specifically shaped as the elongated feature 82 present on the top surface of the lower tool or conveyor.

The elongate structure (which may be pre-formed, as has just been described, or formed during the packaging process) may comprise at least one of a continuous ridge or rib 93 and a corresponding indentation 94 (fig. 13 and 14) extending across the support 2. Alternatively or additionally (see fig. 17 and 18), the elongated structure may comprise a continuous flange 99 extending at the periphery of the respective support 2 above said top plane 95 or below said top plane 95. In fig. 17 and 18, the support 2 is shown with two ridges or ribs 93 and corresponding underlying indentations 94, and a continuous flange 99 extending above or below the top plane 95, at the periphery of the support and forming a kind of peripheral flange, almost at the same level as the rest of the support and only slightly offset above and below compared to the top plane 95.

Each of the one or more elongated structures extends along a respective preferential development ideal median line (i) and has:

-a length (L '), measured along a preferential development ideal line (I'),

a height (H') relative to the top plane 95, measured perpendicular to the top plane 95,

In a currently preferred solution, the length (L ') of each elongated structure is at least 2 times greater than the respective width (W '), wherein the width (W ') is at least 50% of the respective height (H '), and wherein the height (H ') is less than 10 mm.

According to one aspect, the length (L ') of the

elongated structure

93 or 99 may be 5 times or more the width (W') of the elongated structure, and the width (W ') is equal to or greater than the height (H') of the elongated structure: this is the case for example in the embodiments of fig. 13, 14, 17 and 18, which all show highly elongated structures with a reduced height comprised between 0.1 and 5 mm and a width (W') comprised between 0.1 and 30 mm.

In the example of fig. 13 and 14, a ridge or rib 93 projects from the top surface 90 and one or more elongate indentations 94 on the bottom surface extend along and correspond to the elongate ridge; the top and bottom surfaces of the sheet body are flat without the elongated ridges and the elongated indentations and extend along respective parallel top and

bottom planes

95 and 96. Similar to the dimensions of the elongated features, the elongated ridge 93 on the support also projects above the top plane 95 and may have a height H' comprised between 0.1 and 2.0 mm. Further, in one aspect, each of the elongated ridges exhibits a rounded top profile in cross-section.

As for the features on the receiving area 8 of the lower tool, the elongated structures on the support (see the example of fig. 13) may also include: one or more first elongated structures 93 (i.e., elongated ridges or ribs) extending along a first direction; one or more second elongated structures 93 (i.e., elongated ribs or ridges) extending along a second direction at an angle to the first direction; and optionally a third elongate structure extending transverse to both the first elongate feature and the second elongate feature. In fig. 13 and 14, the elongated structure 93 also comprises at least one elongated structure of annular shape extending in correspondence with a peripheral band, which surrounds a central zone of the support 2. Further, in fig. 13 and 14, the support 2 comprises a non-parallel continuous rib, optionally a plurality of non-parallel continuous straight ribs, extending at least across the support 2 above the top plane 95; in this case, the support is substantially in the form of a rectangle and the length of some of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest side of the rectangle.

In fig. 17 and 18, the one or more elongated structures 99 comprise (in addition to or instead of optional ribs similar to those of fig. 13 and 14) a continuous flange extending above or below the top plane 95 at the periphery of the support 2 to a height H' comprised between 0.1 and 10 mm, optionally between 0.1 and 5 mm. The continuous flange completely surrounds the central portion of the support 2 and has an annular shape, optionally a substantially rectangular frame shape. This flange of annular shape is immediately adjacent to the peripheral border of the central portion of the support 2 and presents an upper surface extending on a respective lying plane offset from and below or above the top plane 95 of the support 2 and parallel thereto, wherein the distance between said lying plane and the top plane of the upper surface of the flange is equal to said height (H'). In further detail, in the example of fig. 17 and 18, the elongated structure comprises:

several continuous ribs 93 extending across the support 2 above the top plane 95 and having a width (W'), comprised between 0.1 and 10 mm; and

a continuous flange 99 extending at the periphery of the respective support 2 below or above said top plane 95 (in the example of fig. 18, the continuous flange 99 is not only below the top plane 95, but also below the bottom plane 96); the continuous flange surrounds the entire support and has a closed ring shape, the width (W') of which is comprised between 5 mm and 30 mm.

In general, in order to withstand the substantially uniform mechanical behaviour of the support, the

elongated structures

93 and 99 described above are positioned symmetrically with respect to the axis of symmetry of the support 2.

In all the examples described above, the height H' (in particular the height of the continuous rib or ribs and/or the height of the continuous flange) of the

elongated structure

93 or 99 is less than 5 times the thickness of the support 2, optionally less than 3 times the thickness of the support 2: in other words, the elongated structure imparts a higher out-of-plane stiffness to the support, yet the support maintains an overall planar shape.

Control unit of the device 1

The device according to the invention has at least one control unit 100.

The control unit 100 (schematically represented in the figures) is connected at least to the actuators and/or motors acting on the conveyors, the lower tools, the upper tools, the warehouse and the product loading stations. The control unit is also connected to pumps and valves as part of the vacuum arrangement and the auxiliary vacuum arrangement. The control unit is configured or programmed to perform the steps described above. The control unit may include a digital processor (CPU) with memory (or memories), an analog type circuit, or a combination of one or more digital processing units and one or more analog processing circuits. In the present description and in the claims, the control unit is instructed to be "configured" or "programmed" to perform certain steps: this may in practice be achieved by any means that allow the control unit to be constructed or programmed. For example, in the case where the control unit comprises one or more CPUs, one or more programs are stored in a suitable memory: the program or programs contain instructions which, when executed by the control unit, cause the control unit to perform the steps described or claimed in connection with the control unit. Alternatively, if the control unit is of an analogue type, the circuitry of the control unit is designed to include circuitry configured to process the electrical signals in use so as to perform the control unit steps disclosed herein.

Packaging process

An aspect of the invention relates to a process for packaging a product P arranged on a support 2. The process uses an apparatus according to any one of the appended claims. In one aspect, the packaging process uses one of the apparatuses described above. According to a general aspect, a packaging process comprises the steps of:

-supplying a plastic film 4 from a film supply assembly 3;

-placing at least one support 2 containing a product on a respective receiving area 8 of the base device 6;

-keeping the film portion 4a of said plastic film 4 above said at least one product-containing support 2 positioned in the respective receiving area 8;

-heat-sealing said at least one film portion 4a of said plastic film to said at least one respective one of said product-containing supports 2.

The above process steps may be coordinated by the control unit 100 acting on suitable actuators and/or motors, as described above in connection with the apparatus of any of fig. 1-8.

According to possible variant details, the packaging process may be a vacuum skin packaging process and comprise the following steps:

positioning the upper tool 10 and the lower tool 11 in a first operating condition;

in the case where the upper tool 10 and the lower tool 11 are in the first operating condition,

o suck the gas through the suction orifice 18 and hold the membrane portion 4a against or close to the upper tool action surface,

o heating at least a portion of the film portion 4a held by the upper tool 10,

o placing at least one support 2 containing the product on the respective receiving area 8 of the base device 6 below said membrane portion 4a held by the upper tool 10,

-moving the upper tool 10 and the lower tool 11 to the second operating condition;

in the case where the upper tool 10 and the lower tool 11 are in the second operating condition,

o extracting the gas present between said at least one membrane portion 4a and the underlying support 2 containing the product,

o re-venting the gas through the suction orifice 18 and releasing the film portion 4a, allowing the film portion to drop and heat-seal to the support containing the product, thus forming at least one vacuum skin-packaged product (P).

During the re-venting step, the one or more supports 2 are pressed against the respective receiving areas 8, so that the elongated features 82 engage indentations 94 present on the bottom surface of the support (if the support has preformed ridges and indentations), or so that the peripheral flange 99 rests (see fig. 19) on the peripheral lower tool 11a, while the central portion of the support 2 rests on the central lower tool 11 b. Alternatively, during the re-venting and gas extraction during the packaging cycle, when substantially the top film 4a is attached to the support and the support is pressed against the bottom tool top surface, the formation of elongated structures on the support (such as ribs or ridges 93 and corresponding indentations 94, or such as peripheral flanges 99, which in any case are opposite in shape to the elongated features 82 present on the receiving area) is caused to proceed.

Vacuum skin packaging

The apparatus and process described above may be adapted for making a vacuum skin package containing at least one product, as described in this section and as claimed in any of the appended claims in connection with 'vacuum skin package'. Examples of this type of package are shown in fig. 13 and 14.

The package may be obtained using any of the supports 2 of the type described above. One or more products P are loaded on the support and the film 4 is dropped over the product(s) and welded to the portion of the inner surface of the support not covered by the product(s). The support member presents:

a sheet body having a top surface 90, a bottom surface 91 and a thickness 92,

one or more preformed elongated ridges 93 protruding from the top surface, and

one or more pre-formed elongated indentations 94 on the bottom surface extending along and corresponding to the elongated ridge.

The top and

bottom surfaces

91, 92 of the sheet body are flat without the elongated ridges and the elongated indentations and extend along respective parallel top and

bottom planes

95, 96. In an aspect, at least 75%, optionally 85%, of the top surface of the sheet body is flat.

Each of the elongated ridges 93 projects above said top plane 95 to define a ridge height comprised between 0.1 and 2.0 mm and may present a circular top profile in cross section.

Generally, the plastic film heat-sealed to the support containing the product and the support containing the product are made of respective different materials: in particular, the plastic film and the support may be such that, at atmospheric pressure and at least in the interval between 20 ℃ and 100 ℃, the coefficient of linear expansion per degree celsius of the plastic film in at least one direction is greater than the coefficient of linear expansion per degree celsius in the same direction of the underlying support; thus, when the plastic film material cools after the end of the packaging cycle, the different coefficients of thermal expansion will tend to shrink the plastic film to a greater extent than the underlying support, with the associated result that: in the absence of the elongated ridges 93 and elongated indentations 94 obtained with the apparatus and process of the present invention, the underlying support will tend to bend. In contrast, thanks to the present invention, each support 2 has ridges 93 and indentations 94, which also remain in the packaged product at the end of the packaging cycle and prevent or minimize out-of-plane deflection or bending on portions of the support.

Into further structural detail, the support presents a thickness 92 comprised between 0.10 mm and 2.00 mm, and formed by one of:

-a sheet of paper,

-a sheet of paperboard,

-a multi-layer structure comprising a plurality of paper layers,

-a multilayer structure comprising a plurality of paperboard layers,

-a sheet of plastic material,

-a multilayer structure comprising a plurality of plastic layers,

On the other hand, the plastic film 4 presents a thickness comprised between 20 and 200 microns.

If the process is a vacuum skin packaging process, the film materials described above in the corresponding sections of the description may be used. Plastic films for vacuum skin packaging can have a free shrink (ASTM D2732) at 160 ℃ in both the machine and transverse directions of greater than 3% and optionally less than 20%, preferably less than 15%, even more preferably less than 10%.

As already mentioned, the plastic film 4 used herein shrinks significantly upon cooling. This can be measured by a parameter called residual shrink tension, which is determined as follows.

A sample of the plastic film (2.54 cm x 14.0 cm, 10 cm of which was free for testing) was cut in the Longitudinal (LD) and Transverse (TD) directions and clamped between two jaws, one of which was connected to a load cell. Two jaws hold the sample in the center of the passageway, an impeller blows hot or cold air into the passageway and two thermocouples measure the temperature. The thermocouple was positioned as close as possible to the sample (less than 3 mm) and in the middle of the sample. The signals emitted by the thermocouple (which represents the test temperature) and the load cell (which represents the force) are sent to a computer programmed to record and interpret these signals in detail.

The measurement process provides for the impeller to begin blowing hot air and recording the force released by the sample. The temperature was raised from 25 ℃ to 180 ℃ at a rate of about 2.5 ℃ per second by blowing hot air, and then the temperature was lowered from 180 ℃ to 5 ℃ at a rate of 1.5 ℃ per second by blowing cold air.

Three samples of each film were measured in both the machine direction (LD) and Transverse Direction (TD). The average results are then collected. The residual shrinkage tension at 5 ℃ (expressed in Kg/cm) is then calculated by dividing the force value in Kg measured by the load cell at 5 ℃ by the sample width (expressed in cm) and the average sample thickness (expressed in cm)²Expressed in units). Residual shrink tensions at various temperatures (e.g., at 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5 degrees celsius) can be calculated in a similar manner. The residual shrink tension in both the machine direction and the cross direction at 5 ℃ (which is determined using the above process for plastic films used herein) is at least 3 times greater, optionally at least 5 times greater, than the residual shrink tension at 100 ℃. In other words, as used herein, a film shrinks significantly in both the machine and transverse directions when cooled, thereby inducingThe residual shrinkage tension increases significantly with decreasing temperature.

In the case of a support presenting through holes, then during gas extraction, at least a portion of said extracted gas passes through one or more through holes present in the support. Note that in the examples of fig. 5 and 6, each support presents through holes, and the conveyor comprises a conveyor belt with gas channels and/or porous portions, and during gas extraction, the extracted gas passes through one or more through holes present in the support and through one or more channels or gas permeable portions of the conveyor belt.

Variants

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims. In particular, although the present invention finds its best application in vacuum skin packaging processes and apparatus, it is not excluded that the principles of the present invention may also be applied to any packaging process or apparatus in which a film is thermally bonded to a support and then cooled, thereby shrinking the underlying support and demonstrating the potential disadvantage of bending or undulating it.

Claims

1. An apparatus for packaging products arranged on a support (2), the apparatus comprising:

-a film supply assembly (3) configured for supplying a plastic film (4);

-an upper tool (10) operating above the base means (6) and configured for holding a film portion (4 a) of the plastic film (4) above at least one product-containing support (2) positioned in a respective receiving area, the upper tool (10) and the base means (6) being configured to cooperate for heat-sealing the film portion (4 a) to the at least one product-containing support (2),

characterized in that each reception area (8) comprises:

-one or more elongated features (82) having an active surface extending out of the positioning plane of the flat portion (80),

wherein the one or more elongate features (82) comprise at least one of:

-a continuous rib extending across the respective receiving area above the positioning plane, an

A continuous body extending at the periphery of the respective receiving area above or below the positioning plane,

and wherein each of the one or more elongate features extends along a respective preferential development ideal line and has:

-a length (l) measured along said preferential development ideal line,

-a height (h) relative to the positioning plane (81), measured perpendicular to the positioning plane (81),

-a width (w) measured parallel to said lying plane and perpendicular to said preferential development ideal line,

wherein the length (l) is at least 2 times greater than the width (w),

wherein the width (w) is at least 50% of the height (h),

wherein the height (h) is less than 10 mm.

2. The apparatus as recited in claim 1, wherein the length (l) of each of the elongated features (82) is 5 times or more the width (w) of the elongated feature.

3. The apparatus of claim 2, wherein the width (w) of each of the elongate features (82) is equal to or greater than the height (h) of the elongate feature.

4. The apparatus as claimed in claim 3, wherein the height (h) of each of the elongated features (82) is comprised between 0.1 and 5 mm.

5. Device according to claim 3 or 4, wherein the width of each of the elongated features (82) is comprised between 0.1 and 30 mm.

6. The apparatus of any preceding claim, wherein the one or more elongate features (82) comprise a plurality of elongate features (82) symmetrically positioned relative to an axis of symmetry of the receiving area.

7. The apparatus as set forth in claim 6, wherein the elongated feature (82) includes:

-one or more first elongate features (83) extending along a first direction,

-one or more second elongated features (84) extending along a second direction at an angle to the first direction,

-optionally a third elongate feature (85) extending transverse to both the first and second elongate features.

8. The device according to any one of the preceding claims, wherein the elongated features (82) comprise elongated features (82) extending in correspondence of a peripheral band surrounding a central zone of the respective receiving area (8), and/or wherein the elongated features (82) comprise at least one elongated feature of annular shape extending along the peripheral band.

9. The apparatus of any preceding claim, wherein the one or more elongate features (82) comprise a plurality of non-parallel continuous ribs, optionally a plurality of non-parallel continuous straight ribs, extending at least across the respective receiving area (8) above the positioning plane;

wherein each of the receiving areas (8) is substantially in the form of a rectangle, optionally a square, and the length of each of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest side of the rectangle; or

Wherein each of the receiving areas is substantially in the form of an ellipse, optionally a circle, and the length of each of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest axis of the ellipse.

10. The apparatus of any one of the preceding claims, wherein the one or more elongated features (82) comprise at least one continuous body extending above or below the positioning plane at the periphery of the respective receiving area (8) to a height comprised between 0.1 and 10 mm, optionally between 0.1 and 5 mm.

11. Apparatus according to claim 10, wherein said flat portion (80) of each receiving area is completely surrounded by said at least one respective continuous body having a ring shape, optionally a substantially rectangular frame shape.

12. Apparatus according to claim 11, wherein said continuous body of annular shape is immediately adjacent to said peripheral border of said flat portion (80) and presents an upper surface extending on a respective lying plane staggered from said positioning plane (81) of said flat portion (80).

13. Apparatus according to claim 11 or claim 12, wherein said continuous body upper surface extends, on a lying plane below and parallel to said positioning plane (81) of said flat portion (80), between said positioning plane of said flat portion and said lying plane of said upper surface of said continuous body, for a distance equal to said height (h).

14. Apparatus according to claim 11 or claim 12, wherein said continuous body upper surface extends, on a lying plane above and parallel to said positioning plane (81) of said flat portion (80), between said positioning plane of said flat portion and said lying plane of said upper surface of said continuous body, for a distance equal to said height (h).

15. Apparatus according to any one of the preceding claims, wherein said flat portion of each receiving area and said continuous body are relatively movable one with respect to the other according to a direction perpendicular to said positioning plane (81) for adjusting said height (h).

16. Apparatus according to any one of the preceding claims, wherein each of said elongated features (82) is defined by a respective elongated element removably engaged to said upper side of said base device (6).

17. The apparatus as claimed in any preceding claim wherein each of the elongate features (82) presents a circular top profile in cross-section.

18. Apparatus according to any one of the preceding claims, wherein the base means (6) comprise a lower tool (11) cooperating with the upper tool (10) in correspondence of a packaging station (5) of the apparatus, and wherein the upper tool (10) and the lower tool (11) are relatively displaceable between:

-a first operating condition, in which the upper tool (10) is sufficiently spaced from the lower tool (11) to allow one or more of the product-containing supports (2) to be positioned below the membrane portion (4 a) held by the upper tool (10), and

-a second operating condition, in which said upper tool (10) is approached with respect to said lower tool (11) and is configured to heat-seal said at least one film portion (4 a) to said at least one underlying support (2) containing the product.

19. The apparatus of claim 18, wherein the apparatus comprises:

-a vacuum arrangement (13) configured for removing air at least from the volume between said at least one film portion (4 a) and said one or more product-containing supports (2) located in said packaging station (5);

-suction apertures (18) distributed on the active surface (17) of the upper tool (10) and connected with the vacuum arrangement (13) or auxiliary vacuum arrangement (22);

a control unit (100) configured for controlling the upper and lower tools (10, 11), the heater, the vacuum arrangement and optionally the auxiliary vacuum arrangement,

wherein the control unit (100) is configured to execute the following cycle:

o causing the upper tool (10) and the lower tool (11) to be positioned in the first operating condition,

o in the case of said upper tool (10) and lower tool (11) being in said first operating condition,

-commanding one of the vacuum arrangement (13) or the auxiliary vacuum arrangement (22) to cause suction of gas through the suction aperture (18) and holding the membrane portion (4 a) against or close to the active surface (17),

o causing the upper tool (10) and the lower tool (11) to move to the second operating condition,

-commanding the vacuum arrangement (13) to draw gas present between the at least one membrane portion (4 a) and the underlying product-containing support (2),

-commanding one of said vacuum arrangement (13) or said auxiliary vacuum arrangement (22) to cause the expulsion of gas through said suction orifice for re-evacuation, so as to release said film portion (4 a) from said upper tool (10) active surface and drop said film portion (4 a) onto said support (2) containing the product, said film portion (4 a) being heat-sealed to the upper surface of said support (2) not covered by said product, so as to form at least one vacuum skin-packaged product.

20. The apparatus of claim 18, wherein the apparatus comprises:

-a control unit (100) configured for controlling the conveyor (12), the upper tool (10) and lower tool (11), the heater, the vacuum arrangement and optionally the auxiliary vacuum arrangement,

wherein the control unit (100) is configured to execute the following cycle:

-commanding the heater to cause heating of at least a portion of the membrane portion (4 a) held by the upper tool (10),

-causing the conveyor (12) to position one or more of the product-filled supports (2) on the respective receiving areas (8) of the base means (6) below the film portions (4 a) held by the upper tool (10),

-commanding one of said vacuum arrangement (13) or said auxiliary vacuum arrangement (22) to cause the expulsion of gas through said suction orifice (18) for re-evacuation, so as to release said film portion (4 a) from said upper tool (10) active surface and cause said film portion (4 a) to drop onto said support (2) containing the product, said film portion (4 a) being heat-sealed to the upper surface of said support (2) not covered by said product, so as to form at least one vacuum skin packaged product.

21. The apparatus of claim 20, wherein:

-the receiving area (8) is defined on an upper side of the conveyor (12) configured to traverse the packaging station (5) above the lower tool (11).

22. The apparatus of claim 19, wherein:

-said receiving area (8) is defined on an upper side of said lower tool (11), said upper side directly facing said upper tool (10).

23. Process for packaging products arranged on a support (2) using a device according to any one of the preceding claims, wherein said process comprises the following steps:

-supplying a plastic film (4) from the film supply assembly (3);

-placing at least one support (2) containing a product on said respective receiving area (8) of said base means (6);

24. Process for packaging a product arranged on a support (2) using an apparatus according to any one of the preceding claims 19 or 22, wherein the packaging process comprises the following steps:

-positioning said upper tool (10) and lower tool (11) in said first operating condition;

-in the condition in which said upper tool (10) and lower tool (11) are in said first operating condition,

o sucking gas through the suction orifice (18) and holding the membrane portion (4 a) against or close to the active surface (17),

o heating at least a portion of the film portion (4 a) held by the upper tool (10),

o placing at least one support (2) containing a product on said respective receiving area (8) of said base means (6) below said membrane portion (4 a) held by said upper tool (10),

-moving the upper tool (10) and lower tool (11) to the second operating condition;

-in the case where the upper tool (10) and lower tool (11) are in the second operating condition,

o extracting the gas present between said at least one membrane portion (4 a) and said underlying support (2) containing the product,

o re-venting the gas through said suction orifice (18) and releasing said film portion (4 a), thereby allowing said film portion (4 a) to drop and heat-seal to said product-containing support (2), thereby forming at least one vacuum skin-packaged product (P).

25. Process according to claim 24, wherein, with the upper and lower tools in the second operating condition, in particular during the one or more re-venting and/or gas extraction steps, the one or more supports (2) are pressed against the respective receiving areas (8), causing the formation of elongated structures (93, 99) on the supports (2) that are counter-shaped to the elongated features (82) present on the receiving areas.

26. Process as claimed in claim 25, wherein each of said one or more supports (2) presents:

a sheet body having a top surface, a bottom surface and a thickness,

wherein the top and bottom surfaces of the sheet body are flat and extend along respective parallel top and bottom planes, exclusive of the elongated structures formed during the re-venting and/or gas extraction steps.

27. Process according to any one of the preceding claims 23 to 24, wherein each of said one or more supports (2) has been presented, before being subjected to the packaging process:

a sheet body having a top surface, a bottom surface and a thickness,

-one or more pre-formed elongated structures,

wherein the top and bottom surfaces of the sheet body are planar without the elongated formations and extend along respective parallel top and bottom planes,

wherein the pre-formed elongate formation of each support (2) is positioned over and engages a corresponding elongate feature (82) present on the respective receiving area defined in the base means (6).

28. The process of claim 27, wherein each of the pre-formed elongate structures is counter-shaped to a corresponding one of the elongate features.

29. Process according to any one of claims 23 to 28, wherein the plastic film heat-sealed to the product-containing support (2) and the product-containing support (2) are made of respective different materials.

30. Process according to claim 29, wherein the plastic film has a coefficient of linear expansion per degree celsius in at least one direction greater than the coefficient of linear expansion per degree celsius in the same direction of the underlying support (2) at atmospheric pressure and at least in the interval between 20 ℃ and 100 ℃.

31. Process according to claim 29 or 30, wherein said support (2) presents a thickness comprised between 0.10 mm and 2.00 mm and is formed by one of:

-a sheet of paper,

-a sheet of paperboard,

-a multi-layer structure comprising a plurality of paper layers,

-a multilayer structure comprising a plurality of paperboard layers,

-a sheet of plastic material,

-a multilayer structure comprising a plurality of plastic layers,

32. Process according to any one of claims 29 to 31, wherein said plastic film presents a thickness comprised between 20 and 200 microns.

33. The process of any one of claims 29 to 32, wherein the plastic film is characterized by:

-free shrinkage at 160 ℃ in both the longitudinal and transverse directions (ASTM D2732) of more than 3% and less than 20%, preferably less than 15%, even more preferably less than 10%;

-a residual shrink tension in both the machine direction and the cross direction determined by the process disclosed in the detailed description, the residual shrink tension at 5 ℃ being at least 3 times greater than the residual shrink tension at 100 ℃, optionally at least 5 times greater.

34. Process according to any one of claims 24 to 33, wherein each of said one or more supports (2) presents through holes, and wherein, during gas extraction, at least part of said extracted gas passes through one or more through holes present in said support (2), or

Wherein each of the one or more supports (2) presents through holes, and wherein the conveyor comprises a conveyor belt with gas channels and/or porous portions, and during gas extraction the extracted gas passes through one or more through holes present in the support (2) and through one or more channels or gas permeable portions of the conveyor belt.

35. A vacuum skin package obtained with the process according to any one of claims 23 to 34, the vacuum skin package comprising:

-a support (2) containing the product,

-a plastic film portion (4 a) heat-sealed to the top surface of the support (2) containing the product not covered by the product,

wherein the support (2) presents:

-one or more elongated structures (93; 99),

wherein the top surface (90) and bottom surface (91) of the sheet body are flat without the one or more elongated structures (93; 99) and extend along respective parallel top and bottom planes (95; 96),

wherein each of the one or more elongated structures (93; 99) has an active surface extending out of one or both of the top plane (95) and bottom plane (96),

wherein the one or more elongated structures (99) comprise at least one of:

-a continuous ridge (93) extending across the support (2) above the top plane (95), and

-a continuous flange (99) extending at the periphery of the respective support (2) above the top plane (95) or below the top plane (95), optionally below the bottom plane (96),

and wherein each of the one or more elongated structures extends along a respective preferential development ideal line and has:

-a length (L'), measured along said preferential development ideal line,

-a width (W') measured parallel to the top surface and perpendicular to the preferential development ideal line,

wherein the length (L ') is at least 2 times greater than the width (W'),

wherein the width (W ') is at least 50% of the height (H'),

wherein the height (H') is less than 10 mm.

36. The vacuum skin package of claim 35, wherein the length (L ') of each of the elongate features (93; 99) is 5 times or more the width (W') of the elongate structure.

37. The vacuum skin package of claim 36, wherein the width (W ') of each of the elongated structures (93; 99) is equal to or greater than the height (H') of the elongated structure.

38. Vacuum skin packaging according to claim 37, wherein the height (H') of each of the elongated structures (93; 99) is comprised between 0.1 and 5 mm.

39. Vacuum skin packaging according to claim 36, 37 or 38, wherein the width (W') of each of the elongated structures (93; 99) is comprised between 0.1 and 30 mm.

40. The vacuum skin package of claim 36, 37, 38, or 39, wherein the elongated structure comprises:

-a continuous rib (93) extending across the support (2) above the top plane (95) and having a width (W') comprised between 0.1 and 10 mm; and/or

-a continuous flange (99) extending at the periphery of the respective support (2) below the top plane (95), optionally below the bottom plane (96), and having a width (W') comprised between 5 mm and 30 mm.

41. The vacuum skin package according to any one of claims 35-40, wherein the one or more elongated structures (93; 99) are symmetrically positioned with respect to an axis of symmetry of the support (2).

42. The vacuum skin package of claim 41, wherein the elongated structure (93; 99) comprises:

one or more first elongated structures extending along a first direction,

43. The vacuum skin package according to any one of claims 35-42, wherein the elongated structure (93; 99) comprises an elongated structure extending in correspondence of a peripheral band, the peripheral band surrounding a central area of the support (2), and/or the elongated structure (93; 99) comprises at least one elongated structure of annular shape extending along the peripheral band.

44. The vacuum skin package according to any one of claims 35 to 43, wherein the one or more elongated structures (93) comprise a plurality of non-parallel continuous ribs, optionally a plurality of non-parallel continuous straight ribs, extending at least across the support (2) above the top plane (95);

wherein either each of the supports is substantially in the form of a rectangle, optionally a square, and the length of each of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest side of the rectangle; or each of the supports (2) is substantially in the form of an ellipse, optionally a circle, and the length of each of the non-parallel continuous ribs is at least 75%, optionally at least 90%, of the length of the longest axis of the ellipse.

45. Vacuum skin package according to any one of claims 35 to 44, wherein the one or more elongated structures (99) comprise at least one continuous flange extending above or below the top plane (95) at the periphery of the support (2) to a height (H') comprised between 0.1 and 10 mm, optionally between 0.1 and 5 mm.

46. Vacuum skin packaging according to claim 45, wherein the at least one continuous flange completely surrounds a central portion of the support (2) and has an annular shape, optionally a substantially rectangular frame shape.

47. Vacuum skin packaging according to claim 46, wherein the flange of annular shape is immediately adjacent to the peripheral border of the central portion of the support (2) and presents an upper surface extending on a respective lying plane which is offset from the top plane of the support.

48. Vacuum skin packaging according to claim 47, wherein the flange upper surface extends between a lying plane of the upper surface of the flange and a top plane on a lying plane which lies below and is parallel to the top plane (95) of the support (2) for a distance equal to the height (H').

49. Vacuum skin packaging according to claim 47, wherein the flange upper surface extends between a lying plane of the upper surface of the flange and a top plane on a lying plane which lies above and parallel to the top plane (95) of the support (2) for a distance equal to the height (H').

50. The vacuum skin package of any one of claims 35 to 46, wherein each of the elongated structures (99) exhibits a rounded top profile in cross-section.

51. The vacuum skin package according to any one of claims 35 to 50, wherein the plastic film portion (4 a) heat-sealed to the product-containing support (2) and the product-containing support (2) are made of respective different materials,

wherein the support (2) presents a thickness comprised between 0.10 mm and 2.00 mm and is formed by one of:

-a sheet of paper,

-a sheet of paperboard,

-a multi-layer structure comprising a plurality of paper layers,

-a multilayer structure comprising a plurality of paperboard layers,

-a sheet of plastic material,

-a multilayer structure comprising a plurality of plastic layers,

wherein said plastic film portion (4 a) presents a thickness comprised between 20 and 200 microns;

and wherein the coefficient of linear expansion per DEG C of the plastic film portion (4 a) in at least one direction is greater than the coefficient of linear expansion per DEG C in the same direction of the underlying support (2) at atmospheric pressure and at least in the interval between 20 ℃ and 100 ℃;

optionally wherein the plastic film portion (4 a) is characterized by:

52. Vacuum skin package according to any one of claims 35 to 51, wherein the height (H') of the elongated structure, in particular of the one or more continuous ribs and/or the height of the continuous flange, is lower than 5 times the thickness of the support (2), optionally lower than 3 times the thickness of the support (2).